Continuous process for conversion of lignin to useful compounds

ABSTRACT

This specification discloses an operational continuous process to convert lignin as found in ligno-cellulosic biomass before or after converting at least some of the carbohydrates. The continuous process has been demonstrated to create a slurry comprised of lignin, raise the slurry comprised of lignin to ultra-high pressure, deoxygenate the lignin in a lignin conversion reactor over a catalyst which is not a fixed bed without producing char. The conversion products of the carbohydrates or lignin can be further processed into polyester intermediates for use in polyester preforms and bottles.

PRIORITY AND CROSS REFERENCES

This application claims the priority of U.S. Provisional PatentApplication No. 61/603,217 filed 24 Feb. 2012, U.S. Provisional PatentApplication No. 61/719,486 filed 28 Oct. 2012, U.S. Provisional PatentApplication No. 61/751,919 filed 13 Jan. 2013, U.S. Provisional PatentApplication No. 61/764,611 filed 14 Feb. 2013, U.S. Provisional PatentApplication No. 61/765,402 filed 15 Feb. 2013, and WIPO Application No.PCT/US2013/027393 the teachings of all of which are incorporated intheir entirety.

BACKGROUND

The conversion of lignin in batch processes using hydrogen and catalystsis known. For example, Boocock, D. G. B et al, “The Production ofSynthetic Organic Liquids from Wood Using a Modified Nickel Catalyst”discloses exposing air dried poplar to hydrogen and Raney Nickel in abatch autoclave at 340° C. to 350° C. for 1 or 2 h to produce “oilproducts”. However, according to Boocock et al, “[t]he use of Raneynickel has now been abandoned in favour of nickel from nickel salts . .. ”

The use of catalysts to recover lignin is also known. Zakzeski, PieterC., et al; “The Catalytic Valorization of Lignin for the Production ofRenewable Chemicals”, 2010 is a comprehensive review of catalyticefforts to convert lignin.

While many have proposed theoretical continuous processes, the inventorsare not aware of any disclosure which is enabling beyond a theoreticalbasis. For example, converting solid lignin presents significanthandling problems as documented in PNNL-16079, September 2006.

-   -   “High-pressure feeding systems for biomass slurries have been        recognized as a process development issue at least as long as        the modern biomass conversion systems have been under        development since the Arab oil embargo of 1973. The authors        review the state of the art and various slurry pumping systems,        the vast majority of which include ball check valves. Their        conclusion is that high-pressure feeding remains a problem for        small scale production but believe “the high-pressure feeding of        biomass slurries should be more readily achieved at larger flow        rates wherein the fibrous nature of the biomass would not be        expected to bridge and plug the orifices and valves.”

There exists therefore the need to provide a pumping and charging schemefor slurries.

An example of this is in the series of applications US 2011/0312051, US2011/0312487, US 2011/0312488, US 2011/0313212, US 2011/0313210, US2011/0313209, US 2011/0313208, and US 2011/0312050. These applicationsto common inventors propose a continuous process based only upon batchautoclave results demonstrating high catalytic selectivity to ethyleneglycol. However, the high ethylene glycol yields depend upon the purityof the cellulose feedstock which will intuitively cleave into 3 units ofethylene glycol. Of the experiments listed, the experiments using afeedstock closest to a biomass feedstock as found in the industrial ornatural environment is bleached pulp. However, bleached pulp onlyproduced a yield of 37%. When hemi-cellulose is used (xylose), theresults are expected to be shifted much more away from ethylene glycolto propylene glycol. While the continuous process is theoreticallydescribed, the application fails to disclose an enabling continuousprocess. For example, the disclosure states that “[m]aterials [of acontinuous] process must be capable of being transported from a lowpressure source into the reaction zone, and products must be capable ofbeing transported from the reaction zone to the product recovery zone.Depending upon the mode of operation, residual solids, if any, must becapable of being removed from the reaction zone.” This discloses theintuitively obvious requirement to operate a continuous process but thestatement fails to teach one of ordinary skill how to achieve thoserequirements. Nowhere in the application is this essential problemdiscussed or solved. In fact, during the discussion of FIG. 2 of thepublication, the temperature and pressure conditions are discussedwithout any disclosure as to how the slurry can be raised to the listedpressure of 1800 psig, or even 200 psig. When considering the transportproblem, which, as of 2006, has existed since the oil embargo of 1973, adisclosure telling one of ordinary skill that transport of materials iscritical can hardly be considered enabling.

These series of applications also disclose to keep the water in thereaction zone in the liquid phase. In the batch autoclave this occursdue to the sealed nature. However, it fails to disclose how this isdone, or even if it can be done, in a continuous process.

In order to avoid the problems of pumping and charging as noted, but notsolved, in the above applications and publications, dissolution of thelignin is proposed. WO 2011/117705 relies upon dissolving the lignin sothat the material can be charged as a liquid taking full advantage ofthe check valve and high pressure liquid charging systems. In fact,according to WO 2011/117705, “the only limit [is] that the lignin fed tothe hydrogenolysis reaction is well dissolved, at the feedingtemperature, in said solvent.”

There exists therefore the need for a properly enabling disclosure ofhow to continuously convert lignin which includes the handling,charging, and essential conditions for the process to be carried out.These conditions and steps are believed both novel and inventive and forthe first time experimentally enabled.

SUMMARY

Disclosed in this specification is a continuous process for theconversion of lignin feedstock comprised of lignin and glucans, saidprocess comprising:

-   -   A. Slurry creation of a slurry comprised of lignin from the        lignin feedstock,    -   B. Charging the slurry comprised of lignin into a lignin        conversion reactor having a lignin conversion pressure, wherein        the pressure of the slurry comprised of lignin is higher than        the lignin conversion pressure,    -   C. Converting the lignin of the slurry comprised of lignin into        lignin conversion products by contacting the lignin with        hydrogen in the presence of a first catalyst at a lignin        conversion temperature, and    -   D. Removing the lignin conversion products from the lignin        conversion reactor.

In one embodiment, the slurry creation comprises the steps of chargingthe lignin feedstock comprised of lignin and at least one slurry liquidat 25° C. to a vessel capable of being subjected to vacuum andsubjecting the vessel to vacuum for a time sufficient to disperseparticles of the lignin to greater than 50% of the theoreticaldispersion.

In another embodiment, the slurry creation comprises the steps ofimparting high shear forces to the lignin feedstock and adding a slurryliquid to the lignin feedstock after application of the high shearforces.

In one embodiment, charging the slurry comprised of lignin into thelignin conversion reactor involves pressurizing the slurry comprised oflignin using a piston pump having an inlet valve which can be present inan inlet valve position selected from the group consisting of open,closed and at least partially open, an outlet valve which can be presentin an outlet valve position selected from the group consisting of open,closed and at least partially open, a piston, a piston chamber, withsaid piston being sealed inside and against the piston chamber to form apump cavity, and the pressurizing step comprises:

-   -   A. Passing the slurry comprised of lignin through the inlet        valve which is in the inlet valve position selected from the        group consisting of at least partially open and open into the        pump cavity formed by withdrawing at least a portion of the        piston from the piston chamber, with said outlet valve in the        closed outlet valve position and the pump cavity being at an        inlet pump cavity pressure,    -   B. Changing the inlet valve position to closed,    -   C. Increasing the pressure of the pump cavity to a discharge        pressure by applying a force on the piston in the piston chamber        until the pressure of the slurry comprised of lignin reaches        discharge pressure,    -   E. Discharging at least a portion of the slurry comprised of        lignin from the pump cavity into the lignin conversion reactor        by changing the outlet valve position to a position selected        from the group consisting of at least partially open and open        and forcing the piston further into the pump body to reduce the        volume of the pump cavity and push at least a portion of the        slurry comprised of lignin through the outlet valve;

In one embodiment the inlet valve and the outlet valve are both ballvalves.

In one embodiment, the conversion of lignin of the lignin feedstockfurther comprises deoxygenating the lignin to a plurality of ligninconversion products in a lignin conversion reactor containing reactorcontents comprising a liquid composition which has at least one compoundwhich is liquid at 1 bar and 25° C.; while simultaneously removing atleast some of the reactor contents from the reactor in a continuousmanner; where the lignin conversion occurs at the lignin conversiontemperature and the lignin conversion pressure, wherein the ligninconversion temperature is in the range of greater than the boiling pointof the liquid composition at atmospheric pressure, and less than thecritical temperature of the liquid composition, and the ligninconversion pressure is greater than the bubble pressure of the liquidcomposition at the lignin conversion temperature, subject to thecondition that the lignin conversion pressure is selected so as to avoidthe formation of char.

In one embodiment the lignin conversion in the lignin conversion reactoris accomplished by conducting the continuous catalytic conversion of thelignin feedstock to the lignin conversion products in the presence offree catalyst particles in a lignin conversion reactor, with the ligninconversion reactor having a liquid phase and a gas phase with a liquidlevel at the interface between the liquid phase and the gas phase.

In one embodiment, the removal of the lignin conversion products fromthe lignin conversion reactor is accomplished by removing the ligninconversion products from the lignin conversion reactor at a ligninconversion products removal velocity at a point in the lignin conversionreactor which is higher relative to gravity than the liquid level of thelignin conversion reactor wherein the lignin conversion products removalvelocity is less than a settling velocity of the free catalystparticles.

In one embodiment, the slurry comprised of lignin further compriseswater and at least a portion of the water is separated from the ligninconversion products and used in a step to process a ligno-cellulosicbiomass material, said process step selected from the group consistingof soaking, steam explosion, hydrolysis, fermentation or catalyticconversion of carbohydrates, or the lignin feedstock slurry creationstep (A).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic description of the unit operations of a fullyintegrated process for continuously converting ligno-cellulosic biomassfeedstock to polyester bottles.

FIG. 2 shows a further embodiment of the process.

FIG. 3 shows an embodiment with at least a portion of the water from thelignin conversion process reused in the pre-treatment or slurry creationstep of an integrated facility.

FIG. 4 shows an embodiment of a continuous stir tank reactor for thelignin conversion process.

FIG. 5 shows the effect of mixing type and vacuum upon the finaldispersed concentration versus time.

FIG. 6 shows the schematic of piston pumps and valves used for charginga slurry comprised of lignin to a lignin conversion reactor.

FIG. 7 shows the schematic of piston pumps and valves used for charginga slurry comprised of lignin to a lignin conversion reactor.

FIG. 8 shows the schematic of a bubble column.

FIG. 9 shows the ability of a bubble column to convert the slurrycomprised of lignin to lignin conversion products comparable to thoseattained from a continuous stir tank reactor.

DETAILED DESCRIPTION

This specification is an enabling disclosure and an actual reduction topractice of a continuous lignin conversion process of high yields, inparticular from biomass feedstock. Approximately 80% of the availablelignin in the feedstock is recovered as usable products.

Although not apparent from the numbers, the disclosed process is a veryhigh yield conversion process. In approximate terms, 1 kg of biomassfeedstock used contained 50% lignin, 41% carbohydrates and 9% ash, byweight of the dry feed.

Demonstrated high lignin recovery of the process based upon 1 kg offeedstock are as follows:

50% by dry weight of the feedstock is not lignin and not used, as it iseither destroyed or, in the case of ash, simply not available. Of thelignin remaining, 35-40% by weight of the lignin is oxygen which isremoved from the process (deoxygenated). Thus, while 50% of thefeedstock is lignin, 40% of that weight is unavailable lignin (oxygen),leaving only 30% of the total weight of the feedstock as the theoreticalrecoverable amount of lignin. The experiments below have recovered up to24-26% of the feedstock by weight, or approximately 80% of thetheoretically available lignin has been converted to usable oils.

As noted in the background section, many have proposed continuous ligninand biomass reactors developed on lignin conversion data from batchautoclaves. These previous disclosures have attempted to teach andenable a continuous process. However, these are non-enabling disclosuresand generally inoperative as the processes fail to address the problemsfacing a continuous process.

As an example, the continuous process produced very little long chainaliphatic hydrocarbons, whereas the comparative batch process produced asignificant amount of long chain aliphatic hydrocarbons. It is believedthat the continuous process destroyed the carbohydrates to very lowmolecular weight, low boiling point molecules such as methane and carbondioxide and removed them through the exit gas. In a batch process, thesecompounds are kept in the reactor and are believed to be furtherconverted to long chain aliphatics (greater than 12 carbons). Therefore,in the continuous process of this disclosure, the amount of aliphaticcarbons having a number of carbons greater than 11 expressed as apercent of the total weight of the conversion products is less than 10%by weight, with less than 8% by weight more preferred, with less than 5%by weight even more preferred with less than 2.5% by weight mostpreferred.

The above problem is just one of many encountered by the inventors whentrying to create a continuous process using industrial ligno-cellulosicfeedstocks and not model compounds. These problems make it impossible topredict and enably claim a theoretical continuous process on the basisof batch data or model compounds.

Not only does this specification fully enable one of ordinary skill tooperate a continuous process to convert lignin to liquid oils, thespecification also discloses the subsequent use of the oils to make apolyester bottle or container.

Lignin

The claimed process utilizes a feed or feedstock comprising lignin. Itcan also utilize a feedstock consisting of lignin, or a feedstockconsisting essentially of lignin, or a feedstock comprising at least 95%lignin by weight.

Lignin does not have a single chemical structure. In fact, according tothe Kirk Othmer Encyclopedia, the exact chemical structure of lignin, asit occurs in wood, is not known and because it is hard to extract fromwood without changing its structure, the exact structure may never beknown. While there are many variations of Lignin, the term lignin, asused in this specification, refers to any polymer comprisingp-hydroxyphenyl units, syringyl units, and guaiacyl units.

While pure lignin, such as Organosolv, Acetosolv lignins may be used,the extraction of lignin from its natural origins is expensive usingorganic solvents with the attendant environmental issues. The robustnessof the claimed process is established by the fact is the process isexperimentally demonstrated on a continuous basis to convert lignin aslignin is found in a lignin-cellulosic biomass feedstock.

Lignin Cellulosic Biomass Feedstock

The lignin to be converted in this invention can be present as a feed orfeedstock of natural ligno-cellulosic biomass comprising at least onecarbohydrate and lignin. Depending upon how the natural ligno-cellulosicbiomass is treated another embodiment of the feedstock may have thecomposition and unique decomposition temperatures and surface areasdescribed below.

Because the feedstock may use naturally occurring ligno-cellulosicbiomass, the stream will have relatively young carbon materials. Thefollowing, taken from ASTM D 6866-04 describes the contemporary carbon,which is that found in bio-based hydrocarbons, as opposed tohydrocarbons derived from oil wells, which was derived from biomassthousands of years ago. “[A] direct indication of the relativecontribution of fossil carbon and living biospheric carbon can be asexpressed as the fraction (or percentage) of contemporary carbon, symbolf_(C). This is derived from f_(M) through the use of the observed inputfunction for atmospheric ¹⁴C over recent decades, representing thecombined effects of fossil dilution of the ¹⁴C (minor) and nucleartesting enhancement (major). The relation between f_(C) and f_(M) isnecessarily a function of time. By 1985, when the particulate samplingdiscussed in the cited reference [of ASTM D 6866-04, the teachings ofwhich are incorporated by reference in their entirety] the f_(M) ratiohad decreased to ca. 1.2.”

Fossil carbon is carbon that contains essentially no radiocarbon becauseits age is very much greater than the 5730 year half life of ¹⁴C. Moderncarbon is explicitly 0.95 times the specific activity of SRM 4990b (theoriginal oxalic acid radiocarbon standard), normalized to δ¹³C=−19%.Functionally, the faction of modern carbon=(1/0.95) where the unit 1 isdefined as the concentration of ¹⁴C contemporaneous with 1950 [A.D.]wood (that is, pre-atmospheric nuclear testing) and 0.95 are used tocorrect for the post 1950 [A.D.] bomb ¹⁴C injection into the atmosphere.As described in the analysis and interpretation section of the testmethod, a 100% ¹⁴C indicates an entirely modern carbon source, such asthe products derived from this process. Therefore, the percent ¹⁴C ofthe product stream from the process will be at least 75%, with 85% morepreferred, 95% even preferred and at least 99% even more preferred andat least 100% the most preferred. (The test method notes that thepercent ¹⁴C can be slightly greater than 100% for the reasons set forthin the method). These percentages can also be equated to the amount ofcontemporary carbon as well.

Therefore the amount of contemporary carbon relative to the total amountof carbon is preferred to be at least 75%, with 85% more preferred, 95%even more preferred and at least 99% even more preferred and at least100% the most preferred. Correspondingly, each carbon containingcompound in the reactor, which includes a plurality of carbon containingconversion products will have an amount of contemporary carbon relativeto total amount of carbon is preferred to be at least 75%, with 85% morepreferred, 95% even preferred and at least 99% even more preferred andat least 100% the most preferred.

In general, a natural or naturally occurring ligno-cellulosic biomasscan be one feed stock for this process. Ligno-cellulosic materials canbe described as follows:

Apart from starch, the three major constituents in plant biomass arecellulose, hemicellulose and lignin, which are commonly referred to bythe generic term lignocellulose. Polysaccharide-containing biomasses asa generic term include both starch and ligno-cellulosic biomasses.Therefore, some types of feedstocks can be plant biomass, polysaccharidecontaining biomass, and ligno-cellulosic biomass.

Polysaccharide-containing biomasses according to the present inventioninclude any material containing polymeric sugars e.g. in the form ofstarch as well as refined starch, cellulose and hemicellulose.

Relevant types of naturally occurring biomasses for deriving the claimedinvention may include biomasses derived from agricultural crops selectedfrom the group consisting of starch containing grains, refined starch;corn stover, bagasse, straw e.g. from rice, wheat, rye, oat, barley,rape, sorghum; softwood e.g. Pinus sylvestris, Pinus radiate; hardwoode.g. Salix spp. Eucalyptus spp.; tubers e.g. beet, potato; cereals frome.g. rice, wheat, rye, oat, barley, rape, sorghum and corn; waste paper,fiber fractions from biogas processing, manure, residues from oil palmprocessing, municipal solid waste or the like. Although the experimentsare limited to a few examples of the enumerated list above, theinvention is believed applicable to all because the characterization isprimarily to the unique characteristics of the lignin and surface area.

The ligno-cellulosic biomass feedstock used to derive the composition ispreferably from the family usually called grasses. The proper name isthe family known as Poaceae or Gramineae in the Class Liliopsida (themonocots) of the flowering plants. Plants of this family are usuallycalled grasses, or, to distinguish them from other graminoids, truegrasses. Bamboo is also included. There are about 600 genera and some9,000-10,000 or more species of grasses (Kew Index of World GrassSpecies).

Poaceae includes the staple food grains and cereal crops grown aroundthe world, lawn and forage grasses, and bamboo. Poaceae generally havehollow stems called culms, which are plugged (solid) at intervals callednodes, the points along the culm at which leaves arise. Grass leaves areusually alternate, distichous (in one plane) or rarely spiral, andparallel-veined. Each leaf is differentiated into a lower sheath whichhugs the stem for a distance and a blade with margins usually entire.The leaf blades of many grasses are hardened with silica phytoliths,which helps discourage grazing animals. In some grasses (such as swordgrass) this makes the edges of the grass blades sharp enough to cuthuman skin. A membranous appendage or fringe of hairs, called theligule, lies at the junction between sheath and blade, preventing wateror insects from penetrating into the sheath.

Grass blades grow at the base of the blade and not from elongated stemtips. This low growth point evolved in response to grazing animals andallows grasses to be grazed or mown regularly without severe damage tothe plant.

Flowers of Poaceae are characteristically arranged in spikelets, eachspikelet having one or more florets (the spikelets are further groupedinto panicles or spikes). A spikelet consists of two (or sometimesfewer) bracts at the base, called glumes, followed by one or moreflorets. A floret consists of the flower surrounded by two bracts calledthe lemma (the external one) and the palea (the internal). The flowersare usually hermaphroditic (maize, monoecious, is an exception) andpollination is almost always anemophilous. The perianth is reduced totwo scales, called lodicules, that expand and contract to spread thelemma and palea; these are generally interpreted to be modified sepals.

The fruit of Poaceae is a caryopsis in which the seed coat is fused tothe fruit wall and thus, not separable from it (as in a maize kernel).

There are three general classifications of growth habit present ingrasses; bunch-type (also called caespitose), stoloniferous andrhizomatous.

The success of the grasses lies in part in their morphology and growthprocesses, and in part in their physiological diversity. Most of thegrasses divide into two physiological groups, using the C3 and C4photosynthetic pathways for carbon fixation. The C4 grasses have aphotosynthetic pathway linked to specialized Kranz leaf anatomy thatparticularly adapts them to hot climates and an atmosphere low in carbondioxide.

C3 grasses are referred to as “cool season grasses” while C4 plants areconsidered “warm season grasses”. Grasses may be either annual orperennial. Examples of annual cool season are wheat, rye, annualbluegrass (annual meadowgrass, Poa annua and oat). Examples of perennialcool season are orchard grass (cocksfoot, Dactylis glomerata), fescue(Festuca spp), Kentucky Bluegrass and perennial ryegrass (Loliumperenne). Examples of annual warm season are corn, sudangrass and pearlmillet. Examples of Perennial Warm Season are big bluestem, indiangrass, bermuda grass and switch grass.

One classification of the grass family recognizes twelve subfamilies:These are 1) anomochlooideae, a small lineage of broad-leaved grassesthat includes two genera (Anomochloa, Streptochaeta); 2) Pharoideae, asmall lineage of grasses that includes three genera, including Pharusand Leptaspis; 3) Puelioideae a small lineage that includes the Africangenus Puelia; 4) Pooideae which includes wheat, barley, oats,brome-grass (Bronnus) and reed-grasses (Calamagrostis); 5) Bambusoideaewhich includes bamboo; 6) Ehrhartoideae, which includes rice, and wildrice; 7) Arundinoideae, which includes the giant reed and common reed;8) Centothecoideae, a small subfamily of 11 genera that is sometimesincluded in Panicoideae; 9) Chloridoideae including the lovegrasses(Eragrostis, ca. 350 species, including teff), dropseeds (Sporobolus,some 160 species), finger millet (Eleusine coracana (L.) Gaertn.), andthe muhly grasses (Muhlenbergia, ca. 175 species); 10) Panicoideaeincluding panic grass, maize, sorghum, sugar cane, most millets, fonioand bluestem grasses; 11) Micrairoideae and 12) Danthoniodieae includingpampas grass; with Poa which is a genus of about 500 species of grasses,native to the temperate regions of both hemispheres.

Agricultural grasses grown for their edible seeds are called cereals.Three common cereals are rice, wheat and maize (corn). Of all crops, 70%are grasses.

Sugarcane is the major source of sugar production. Grasses are used forconstruction. Scaffolding made from bamboo is able to withstand typhoonforce winds that would break steel scaffolding. Larger bamboos andArundo donax have stout culms that can be used in a manner similar totimber, and grass roots stabilize the sod of sod houses. Arundo is usedto make reeds for woodwind instruments, and bamboo is used forinnumerable implements.

Another naturally occurring ligno-cellulosic biomass feedstock may bewoody plants or woods. A woody plant is a plant that uses wood as itsstructural tissue. These are typically perennial plants whose stems andlarger roots are reinforced with wood produced adjacent to the vasculartissues. The main stem, larger branches, and roots of these plants areusually covered by a layer of thickened bark. Woody plants are usuallyeither trees, shrubs, or lianas. Wood is a structural cellularadaptation that allows woody plants to grow from above ground stems yearafter year, thus making some woody plants the largest and tallestplants.

These plants need a vascular system to move water and nutrients from theroots to the leaves (xylem) and to move sugars from the leaves to therest of the plant (phloem). There are two kinds of xylem: primary thatis formed during primary growth from procambium and secondary xylem thatis formed during secondary growth from vascular cambium.

-   -   What is usually called “wood” is the secondary xylem of such        plants.    -   The two main groups in which secondary xylem can be found are:    -   1) conifers (Coniferae): there are some six hundred species of        conifers. All species have secondary xylem, which is relatively        uniform in structure throughout this group. Many conifers become        tall trees: the secondary xylem of such trees is marketed as        softwood.    -   2) angiosperms (Angiospermae): there are some quarter of a        million to four hundred thousand species of angiosperms. Within        this group secondary xylem has not been found in the monocots        (e.g. Poaceae). Many non-monocot angiosperms become trees, and        the secondary xylem of these is marketed as hardwood.

The term softwood useful in this process is used to describe wood fromtrees that belong to gymnosperms. The gymnosperms are plants with nakedseeds not enclosed in an ovary. These seed “fruits” are considered moreprimitive than hardwoods. Softwood trees are usually evergreen, bearcones, and have needles or scale like leaves. They include coniferspecies e.g. pine, spruces, firs, and cedars. Wood hardness varies amongthe conifer species.

The term hardwood useful for this process is used to describe wood fromtrees that belong to the angiosperm family. Angiosperms are plants withovules enclosed for protection in an ovary. When fertilized, theseovules develop into seeds. The hardwood trees are usually broad-leaved;in temperate and boreal latitudes they are mostly deciduous, but intropics and subtropics mostly evergreen. These leaves can be eithersimple (single blades) or they can be compound with leaflets attached toa leaf stem. Although variable in shape all hardwood leaves have adistinct network of fine veins. The hardwood plants include e.g. Aspen,Birch, Cherry, Maple, Oak and Teak.

Therefore a preferred naturally occurring ligno-cellulosic biomass maybe selected from the group consisting of the grasses and woods. Anotherpreferred naturally occurring ligno-cellulosic biomass can be selectedfrom the group consisting of the plants belonging to the conifers,angiosperms, Poaceae and families. Another preferred naturally occurringligno-cellulosic biomass may be that biomass having at least 10% byweight of it dry matter as cellulose, or more preferably at least 5% byweight of its dry matter as cellulose.

The carbohydrate(s) comprising the invention is selected from the groupof carbohydrates based upon the glucose, xylose, and mannose monomersand mixtures thereof.

The feedstock comprising lignin can be naturally occurringligno-cellulosic biomass that has been ground to small particles, or onewhich has been further processed. One process for creating the feedstockcomprising lignin, comprises the following steps.

Preferable Pretreatment

It has been theorized that pretreatment of the feedstock is a solutionto the challenge of processing an insoluble solid feedstock comprisinglignin or polysaccharides in a pressurized environment. According to US2011/0312051, sizing, grinding, drying, hot catalytic treatment andcombinations thereof are suitable pretreatment of the feedstock tofacilitate the continuous transporting of the feedstock. While notpresenting any experimental evidence, US 2011/0312051 claims that mildacid hydrolysis of polysaccharides, catalytic hydrogenation ofpolysaccharides, or enzymatic hydrolysis of polysaccharides are allsuitable to create a transportable feedstock. US 2011/0312051 alsoclaims that hot water treatment, steam treatment, thermal treatment,chemical treatment, biological treatment, or catalytic treatment mayresult in lower molecular weight polysaccharides and depolymerizedlignins that are more easily transported as compared to the untreatedones. While this may help transport, there is no disclosure or solutionto how to pressurize the solid/liquid slurry resulting from thepre-treatment. In fact, as the inventors have learned the conventionalwisdom and conventional systems used for pressuring slurries failed whenpre-treated ligno-cellulosic biomass feedstock is used.

In the integrated second generation industrial operations, pre-treatmentis often used to ensure that the structure of the ligno-cellulosiccontent is rendered more accessible to the catalysts, such as enzymes,and at the same time the concentrations of harmful inhibitoryby-products such as acetic acid, furfural and hydroxymethyl furfuralremain substantially low. There are several strategies to achieveincreased accessibility, many of which may yet be invented.

The current pre-treatment strategies imply subjecting theligno-cellulosic biomass material to temperatures between 110-250° C.for 1-60 min e.g.:

Hot water extractionMultistage dilute acid hydrolysis, which removes dissolved materialbefore inhibitory substances are formedDilute acid hydrolyses at relatively low severity conditionsAlkaline wet oxidationSteam explosion.

A preferred pretreatment of a naturally occurring ligno-cellulosicbiomass includes a soaking of the naturally occurring ligno-cellulosicbiomass feedstock and a steam explosion of at least a part of the soakednaturally occurring ligno-cellulosic biomass feedstock.

The soaking occurs in a substance such as water in either vapor form,steam, or liquid form or liquid and steam together, to produce aproduct. The product is a soaked biomass containing a first liquid, withthe first liquid usually being water in its liquid or vapor form or somemixture.

This soaking can be done by any number of techniques that expose asubstance to water, which could be steam or liquid or mixture of steamand water, or, more in general, to water at high temperature and highpressure. The temperature should be in one of the following ranges: 145to 165° C., 120 to 210° C., 140 to 210° C., 150 to 200° C., 155 to 185°C., 160 to 180° C. Although the time could be lengthy, such as up to butless than 24 hours, or less than 16 hours, or less than 12 hours, orless than 9 hours, or less than 6 hours; the time of exposure ispreferably quite short, ranging from 1 minute to 6 hours, from 1 minuteto 4 hours, from 1 minute to 3 hours, from 1 minute to 2.5 hours, morepreferably 5 minutes to 1.5 hours, 5 minutes to 1 hour, 15 minutes to 1hour.

If steam is used, it is preferably saturated, but could be superheated.The soaking step can be batch or continuous, with or without stirring. Alow temperature soak prior to the high temperature soak can be used. Thetemperature of the low temperature soak is in the range of 25 to 90° C.Although the time could be lengthy, such as up to but less than 24hours, or less than 16 hours, or less than 12 hours, or less than 9hours or less than 6 hours; the time of exposure is preferably quiteshort, ranging from 1 minute to 6 hours, from 1 minute to 4 hours, from1 minute to 3 hours, from 1 minute to 2.5 hours, more preferably 5minutes to 1.5 hours, 5 minutes to 1 hour, 15 minutes to 1 hour.

Either soaking step could also include the addition of other compounds,e.g. H₂SO4, NH₃, in order to achieve higher performance later on in theprocess. However, it is preferred that acid, base or halogens not beused anywhere in the process or pre-treatment. The feedstock ispreferably void of added sulfur, halogens, or nitrogen. The amount ofsulfur, if present, in the composition is in the range of 0 to 1% by dryweight of the total composition. Additionally, the amount of totalhalogens, if present, are in the range of 0 to 1% by dry weight of thetotal composition. By keeping halogens from the feedstock, there are nohalogens in the lignin conversion products.

The product comprising the first liquid is then passed to a separationstep where the first liquid is separated from the soaked biomass. Theliquid will not completely separate so that at least a portion of theliquid is separated, with preferably as much liquid as possible in aneconomic time frame. The liquid from this separation step is known asthe first liquid stream comprising the first liquid. The first liquidwill be the liquid used in the soaking, generally water and the solublespecies of the feedstock. These water soluble species are glucan, xylan,galactan, arabinan, glucolygomers, xyloolygomers, galactolygomers andarabinolygomers. The solid biomass is called the first solid stream asit contains most, if not all, of the solids.

The separation of the liquid can again be done by known techniques andlikely some which have yet to be invented. A preferred piece ofequipment is a press, as a press will generate a liquid under highpressure.

The first solid stream is then steam exploded to create a steam explodedstream, comprising solids and a second liquid. Steam explosion is a wellknown technique in the biomass field and any of the systems availabletoday and in the future are believed suitable for this step. Theseverity of the steam explosion is known in the literature as Ro, and isa function of time and temperature and is expressed as

Ro=texp[(T−100)/14.75]

with temperature, T expressed in Celsius and time, t, expressed incommon units.

The formula is also expressed as Log(Ro), namely

Log(Ro)=Ln(t)+[(T−100)/14.75].

Log(Ro) is preferably in the ranges of 2.8 to 5.3, 3 to 5.3, 3 to 5.0and 3 to 4.3.

The steam exploded stream may be optionally washed at least with waterand there may be other additives used as well. It is conceivable thatanother liquid may be used in the future, so water is not believed to beabsolutely essential. At this point, water is the preferred liquid andif water is used, it is considered the third liquid. The liquid effluentfrom the optional wash is the third liquid stream. This wash step is notconsidered essential and is optional.

The washed exploded stream is then processed to remove at least aportion of the liquid in the washed exploded material. This separationstep is also optional. The term at least a portion is removed, is toremind one that while removal of as much liquid as possible is desirable(pressing), it is unlikely that 100% removal is possible. In any event,100% removal of the water is not desirable since water is needed for thesubsequent hydrolysis reaction. The preferred process for this step isagain a press, but other known techniques and those not invented yet arebelieved to be suitable. The products separated from this process aresolids in the second solid stream and liquids in the second liquidstream.

The steam exploded stream is then subjected to hydrolysis to create ahydrolyzed stream. Optionally at least a part of the liquid of the firstliquid stream is added to the steam exploded stream. Also, water isoptionally added. Hydrolysis of the steam exploded stream is realized bycontacting the steam exploded stream with a catalyst. Enzymes and enzymecomposition is the preferred catalyst. While laccase, an enzyme known toalter lignin, may be used, the composition is preferably void of atleast one enzyme which converts lignin. A preferred hydrolysis of thesteam exploded stream comprises the step of:

-   -   A) Contacting the steam exploded stream with at least a portion        of a solvent, the solvent comprised of water soluble hydrolyzed        species; wherein at least some of the water soluble hydrolyzed        species are the same as the water soluble hydrolyzed species        obtainable from the hydrolysis of the steam exploded stream;    -   B) maintaining the contact between the steam exploded stream and        the solvent at a temperature in the range of 20° C. to 200° C.        for a time in the range of 5 minutes to 72 hours to create a        hydrolyzed stream from the steam exploded stream.

The hydrolyzed stream is comprised of carbohydrate monomers selectedfrom the group consisting of glucose, xylose, and mannose.

The hydrolyzed stream is subjected to fermentation to create a fermentedstream comprised of the composition and water. The fermentation isperformed by means of addition of yeast or yeast composition to thehydrolyzed stream.

Eventually hydrolysis and fermentation can be performed simultaneously,according to the well known technique of simultaneous saccharificationand fermentation (SSF).

The composition derived from naturally occurring ligno-cellulosicbiomass is separated from the water in the fermented stream. Theseparation of the liquid can be done by known techniques and likely somewhich have yet to be invented. A preferred piece of equipment is apress.

The composition is different from naturally occurring ligno-cellulosicbiomass in that it has a large surface area as calculated according tothe standard Brunauer, Emmett and Teller (BET) method.

The BET surface area of the dry composition is at least 4 m²/gm morepreferably in the range of 4 to 80 m²/gm, with 4 to 50 m²/gm being morepreferable, 4 to 25 m²/gm being even more preferred, and 4 to 15 m²/gmbeing even more preferred and 4 to 12 m²/gm being the most preferred.

The composition is further characterized by the peaks generated during athermal gravimetric analysis, known as TGA.

In thermogravimetric analysis, the plot of the weight with respect totemperature and the plot of the first derivative of weight with respectto temperature are commonly used.

If the decomposition of the material or of a component of the materialoccurs in a specific range of temperature, the plot of the firstderivative of weight with respect to temperature presents a maximum inthe specific range of temperature, defined also as first derivativepeak. The value of temperature corresponding to the first derivativepeak is considered the decomposition temperature of the material or ofthat component of the material.

The material is a composition of many components, which decompose indifferent specific temperature ranges, the plot of the first derivativeof weight with respect to temperature presents first derivative peaksassociated to the decomposition of each component in each specifictemperature range. The temperature values corresponding to the firstderivative peaks are considered the decomposition temperatures of eachcomponent of the material.

As a general rule, a maximum is located between two minima. The valuesof temperature corresponding to the minima are considered as the initialdecomposition temperature and the final decomposition temperature of thedecomposition temperature range of the component whose decompositiontemperature corresponds to the first derivative peak comprised betweenthe two minima. In this way, a derivative peak corresponds todecomposition temperature range. The weight loss of the material in therange between the initial decomposition temperature and the finaldecomposition temperature is associated to the decomposition of thatcomponent of the material and to the first derivative peak.

Should the naturally occurring ligno-cellulosic biomass used to derivethe lignin composition be a mixture of different species of grasses orplants or other materials, then the mixture of the naturally occurringligno-cellulosic biomass is what should be used for the comparison withthe material from which the composition was derived.

The composition created has the characteristics that temperaturecorresponding to the maximum value of the first lignin decompositionpeak is less than the temperature corresponding to the maximum value ofthe first lignin decomposition peak of the naturally occurringligno-cellulosic biomass. This difference is marked with the maximumvalue of the first lignin decomposition peak being less than thetemperature corresponding to the maximum value of the first lignindecomposition peak of the naturally occurring ligno-cellulosic biomassby a value selected from the group consisting of at least 10° C., atleast 15° C., at least 20° C., and at least 25° C.

This reduction in the maximum value of the first lignin decompositiontemperature can be compared to the maximum value of the first lignindecomposition temperature after pre-treatment.

Additionally, the absolute mass on a dry basis associated with the firstlignin decomposition peak of the claimed lignin composition is greaterthan the absolute mass on a dry basis of the second lignin decompositionpeak. While for Arundo donax, the absolute mass of the firstdecomposition temperature of the naturally occurring ligno-cellulosicbiomass is greater than the absolute mass of the second decompositiontemperature of the naturally occurring ligno-cellulosic biomass, this isnot true for many ligno-cellulosic biomasses such as corn stover andwheat straw. However, after conversion, the lignin composition derivedfrom these biomasses has a mass on a dry basis associated with the firstlignin decomposition temperature that is greater than the mass on a drybasis associated with the second lignin decomposition temperature.

The feedstock can be further characterized by comparing the temperatureassociated with the maximum value of the first lignin decompositionrange with the temperature associated with the maximum value of thefirst lignin decomposition range of the ligno-cellulosic biomass used toderive the feedstock.

The feedstock can also be further characterized by the relative amountof carbohydrates, which include glucans and xylans, present on a drybasis. The composition may have the amount of total carbohydratespresent in the composition in the range of 10 to 60% of the dry weightof the composition, with 10 to 40% more preferred with 5 to 35% evenmost preferred. Provided, of course, that the amount of total ligninpresent in the composition is in the range of 30 to 80% of the dryweight of the composition and the weight percent of the carbohydratesplus the weight percent of the lignin is less than 100% of the dryweight of the feedstock.

Because the composition of the feedstock comprising lignin may vary withthe starting material from which it is derived, the naturally occurringligno-cellulosic biomass from which the feedstock is derived can beselected from the group consisting of the grasses and food crops.

Slurry Creation

Lignin may be charged to a lignin conversion reactor (500) as a solidslurried in a liquid. In a preferred embodiment the liquid may comprisewater. In another embodiment, the liquid may comprise a hydrogen donor.The use of hydrogen donors is well known and described in Wang, X, andRinaldi, R.; “Exploiting H-Transfer reactions with RANEY® Ni for upgradeof phenolic and aromatic biorefinery feeds under unusual, low severityconditions:”, Energy Environ. Sci., 2012, 5, 8244

It has been discovered that a slurry comprised of lignin has severalunique characteristics making it difficult to create, maintain andhandle, and in many instances a slurry comprised of lignin behaves inthe opposite manner of traditional slurries.

The solid content of a slurry comprised of lignin should be in the rangeof about 1 to 70% by weight with 5 to 35% by weight solids content morepreferred. Traditionally, slurries are easier to maintain when thesolids content is low. Surprisingly, a slurry comprised of lignin iseasier to maintain when the solids content is high (greater than 20% byweight solids).

The particle size of the slurry comprised of lignin should be such thatthe number average size is in the range of less than 200 micron withless than 150 micron being preferred and less than 100 micron being mostpreferred. Particle size reduction is not necessary when the feedstockcomprising lignin has been steam exploded. However, particle sizereduction is considered necessary if the practitioner is starting withnaturally occurring lignin, such as wood chips.

No surfactants or emulsifying agents are needed, but they can be used.

There are several strategies for creating a slurry comprised of lignindepending upon the manufacturing location of the claimed process. If thelignin conversion is co-sited with the pre-treatment or carbohydrateconversion of the ligno-cellulosic biomass (10), then the lignin mayalready be present in a slurry form, often called the stillage orstillage lignin, with little or no water soluble sugars, or void ofwater soluble sugars. When the ligno-cellulosic biomass (10) is passedthrough the pre-treatment or carbohydrate conversion process first, thewater soluble sugars are converted to species other than sugars. Thewater soluble sugars will have been washed off, extracted or convertedby the enzymes or catalysts to species other than sugars, leaving thebottoms which are comprised of lignin and unconverted, insolublecarbohydrates, many of which are still bound with the lignin. Thesebottoms are void of or substantially void of free water soluble sugars.

In this iterated embodiment, the bottoms, (or stillage or stillagelignin as it is often called), of the sugar or carbohydrate conversionprocess, (e.g. fermentation), are passed directly to a next processwhich could further remove more carbohydrates; or the bottoms are passeddirectly to the lignin conversion process described herein. In thismanner, the water from the carbohydrate conversion process which wouldotherwise have to be treated via expensive waste water treatmentplant(s) is used as a slurry liquid to maintain or create the slurrycomprised of lignin to feed the lignin conversion process. The stillagelignin, which is the slurry liquid removed from the carbohydrateconversion process comprising the lignin, is then cleaned in situ by thehydrogen of the lignin conversion process while at the same time,converting the lignin. As described later, the slurry liquid coming fromthe lignin conversion process will have significantly less totalbiochemical oxygen demand, also known as BOD's, and/or chemical oxygendemand, also known as COD's, relative to the amounts of BOD's and COD'sin the incoming slurry liquid from the stillage lignin, thus reducingthe amount of, and cost of waste water treatment needed before releasingthe slurry liquid to the environment. The BOD's and COD's have beenchemically destroyed by the conditions of the lignin conversion process.

In a further refinement, at least a portion of the slurry liquid fromthe lignin conversion process can be used as make up water or steam in apre-treatment process, thus significantly reducing the amount and costof water treatment. (See FIG. 3)

This schematic is demonstrated in FIG. 3, wherein the ligno-cellulosicbiomass (10) enters the pre-treatment process and the pre-treatedligno-cellulosic biomass is passed to the carbohydrate conversionprocess, in this instance fermentation. In the carbohydrate conversionprocess, the sugars are converted to the final product or products. Itis preferable to introduce the slurry liquid from the lignin conversionprocess (620), prior to or simultaneously with the steam explosion stepof the pretreatment process.

The bottoms, or stillage, comprising the lignin, slurry liquid, andpossibly carbohydrates, is passed to the slurry creation step, (300). Ifthe stillage lignin is a sufficiently stable slurry and of desiredconcentrations, (e.g. solids, buffers, pH), it can be passed directly to(400), the slurry pump, without any further treatment, e.g. waterdilution or water reduction, agitation, vacuum.

If adjustments are needed, the slurry comprised of lignin is brought tothe optimum slurry conditions by adjusting the solids concentrationunder agitation and optionally vacuum. Usually this is under high shearagitation of the slurry comprised of lignin.

In some embodiments, the bottoms of the carbohydrate conversion processwill be shipped to a different location for the lignin conversion. Whileit is possible to ship the already slurried stillage, the cost ofshipping water may make shipping cost prohibitive. In this instance, itis anticipated that the feedstock comprised of lignin will be shipped asa solid and often dry with as much water having been removed aspossible; usually by a filter press, drying, or both. Oftentimes, thesolid feedstock comprising lignin will be chilled or even frozen toprevent microbial growth during shipment or storage. The slurry liquidfrom the dewatering process is often sent to waste water treatment whereit is cleaned to remove BOD's and COD's, and then released to theenvironment or reused in parts of the pre-treatment process. It is thisexternal treatment step which can be minimized or reduced by re-using orrecycling at least a portion of the slurry liquid from the ligninconversion process.

It has been directly observed that the feedstock comprising lignin isexcessively intractable and the particles are very difficult toseparate. This is particularly the case when the feedstock comprisinglignin has been subjected to dewatering pressure to dewater, as in afilter press. Visible light microscopic examination shows the feedstockcomprising lignin to have tendrils with tentacles and hooks, much likeVelcro®.

As stated earlier, if the feedstock after the carbohydrate conversionstep is already a slurry, it may be possible to add the slurry directlyto the process without further treatment. However, generally this is notexpected. After carbohydrate conversion, there is likely to be trappedgasses in the stillage lignin which should be removed.

If the lignin conversion is not co-sited with the pre-treatment orfermentation of the ligno-cellulosic biomass (10), then one strategy forcreating the slurry comprised of lignin is to use a machine capable ofapplying high shear forces and apply high shear forces to the unslurriedsolid feedstock comprising lignin. High shear forces may be achieved byfeeding the solid feedstock comprising lignin through a compounder.Preferred compounder embodiments include a twin screw co-rotating screwscompounder, a twin screw counter-rotating screws compounder, anextruder, a banbury, or another device known for imparting mechanicalforces to the material processed through it.

The amount of mechanical forces required is related to the amount ofenergy required to make the solid feedstock comprising lignin readilydispersible. The more mechanical forces applied to the solid feedstockcomprising lignin, the easier the dispersion. The amount of mechanicalforces required can be determined iteratively by comparing the energyconsumed with the energy required to disperse the resulting solid intothe slurry liquid of the slurry. Techniques to vary the amount and typeof mechanical forces applied to the solid feedstock comprising lignindepend upon the equipment and are well known in the art to thosefamiliar with the particular machine being used.

A slurry liquid can be added to the solid feedstock comprising lignin toproduce a slurry comprised of lignin. It is preferred that the slurryliquid be added to the solid feedstock comprising lignin after exitingthe compounder. In this regard, the solid feedstock comprising lignin isvoid of free liquid meaning that free liquid comprises less than 5% ofthe weight of the composition with no free liquid being preferred. Inanother embodiment, the slurry liquid may be added to the solidfeedstock comprising lignin in the compounder. In a preferred embodimentthe slurry liquid comprises water. In another embodiment, the slurryliquid may comprise a hydrogen donor. It should be noted that for thepurposes of this specification, the slurry liquid is also known as acarrier liquid as well.

The amount of energy consumed by the compounder necessary to create asolid feedstock comprising lignin that is readily dispersible into aslurry liquid and/or has a low viscosity when dispersed into a slurryliquid can be determined by measuring the torque. The solid feedstockcomprising lignin is readily dispersed into a slurry liquid when theamount of torque required to disperse the solid feedstock comprisinglignin into the slurry liquid in the absence of a hydrolysis catalyst isless than 50% of the amount of torque required to disperse the solidfeedstock comprising lignin into the slurry liquid under the sameconditions, prior to the application of the mechanical forces.

The amount of torque is the total amount of energy applied to thesolid-slurry liquid mixture to disperse the solid into the slurryliquid. The amount of torque can be determined by the area under thecurve of the line of the torque applied at a given point in time, t,corresponding to the point at which the solid is considered dispersedinto the slurry liquid. A solid is considered dispersed into the slurryliquid when the numeral average of the percent of dry matter content ofa statistically valid number of aliquots of the slurry liquid is within2.5% of the percent of the total dry matter content in the slurryliquid.

The viscosity of the slurry comprised of lignin, measured at 25° C., ashear rate of 10s-1, of the mechanically dispersed solid feedstockcomprising lignin dispersed in the slurry liquid content should be lessthan the viscosity of a slurry of the solid feedstock comprised oflignin dispersed in the slurry liquid prior to mechanical treatment;when measured under the same conditions (e.g. dry matter content).

After producing the slurry comprised of lignin, the slurry comprised oflignin may be maintained by way of mechanical agitation.

Another strategy for creating the slurry comprised of lignin where thelignin conversion is not co-sited with the pre-treatment or fermentationof the ligno-cellulosic biomass (10) is to expose the solid feedstockcomprising lignin in a slurry liquid, preferably water, to a vacuum orpressure less than atmospheric pressure, with less than 0.8 bar beingpreferred, with less than 0.7 bar being more preferred, less than 0.4bar being even more preferred with less than 0.2 bar being the mostpreferred. The feedstock comprising lignin will rapidly expand intosmall particles, disassociate, and disperse. In this way, high shearmixing and/or high shear forces are avoided with higher concentrationspossible. It is preferred to have at least some mechanical agitationoccurring simultaneously with the vacuum step so as to more rapidlydisperse the particles. The Slurry Creation Experimental Section andFIG. 5 quantitatively show the advantage of using vacuum on the solidfeedstock comprising lignin prior to increasing the pressure on theslurry. The vacuum may be applied simultaneously with shear andagitation, through a conveying screw. The minimum time for the vacuum toremain applied is the time sufficient to disperse the particles togreater than 50% of the theoretical dispersion at 25° C., with greaterthan 75% dispersion at 25° C. more preferred and greater than 90%dispersion at 25° C. the most preferred. It is preferred that the solidfeedstock comprising lignin be surrounded or encompassed by a slurryliquid for full effectiveness of the vacuum. In a preferred embodimentthis slurry liquid is water. In another embodiment, this slurry liquidcomprises a hydrogen donor. 100% dispersion at 25° C. is the theoreticaldispersion. The amount of dispersion is determined by measuring theamount of solids in a sample after 2 minutes of settling. If there were16 gms of solid in 84 gms of liquid, the dry matter content at 100%dispersion would be 16%. At 50% of the theoretical dispersion, the drymatter content of the sample after 2 minutes of settling would be 8%.

A final strategy for creating the slurry comprised of lignin where thelignin conversion is not co-sited with the pre-treatment or fermentationof the ligno-cellulosic biomass (10) is to expose the solid feedstockcomprising lignin in a slurry liquid, preferably water, to high shearsuch as that found in a blender, which over time will also disperse theparticles of the feedstock comprising lignin throughout the slurry. Inanother embodiment, the slurry liquid is a hydrogen donor.

In most instances the slurry liquid will be water or water incombination with at least one hydrogen donor. The ratio amount of theweight of the water of the slurry liquid to the dry weight of the ligninfeedstock is preferably in the range of 0.3 to 9, with 0.5 to 9 morepreferred, with 1 to 9 even more preferred with 2 to 9 another preferredratio and 3 to 5 an even more preferred ratio.

Slurry Creation Experiments

Experiments were conducted for evaluating slurry preparation undervacuum treatment in comparison with slurry preparation under standardmechanical agitation.

Slurry Creation Experiment 1

An amount of 450 g of lignin-rich composition, having a dry matter of53%, was inserted into a 3 liter round bottom flask with 1050 g ofwater, to reach a theoretical concentration of 16% of dry matter oflignin-rich composition in the mixture. No mechanical mixing wasapplied.

The flask had a dimension of approximately 16 cm and was equipped with astirrer with a dimension of approximately 6 cm.

The flask was sealed and vacuum of 29.8 mmHg was applied for 5 minutesand removed. After 2 minutes of sedimentation time, a first sampling ofthe slurry comprised of lignin was extracted.

Mechanical agitation was applied to the slurry comprised of lignin atatmospheric pressure for 1 minute, then mechanical agitation was stoppedand after 2 minutes of sedimentation time a sampling was extracted. Themechanical agitation procedure was repeated further for 5, 10, 30, and60 minutes of agitation time and samplings were extracted after asedimentation time of 2 minutes each time.

No chunks were present at the bottom of the flask and the slurrycomprised of lignin appeared to be homogeneously mixed.

Slurry Creation Experiment 2

A control experiment was realized by inserting an amount of 450 g oflignin-rich composition, having a dry matter of 53%, into a 3 literround bottom flask with 1050 g of water, to reach a theoreticalconcentration of 16% of dry matter of lignin-rich composition in themixture.

The flask and mechanical stirrer were the same as in the experimentconducted with vacuum. The slurry comprised of lignin was subjected onlyto mechanical agitation, and samplings were extracted after 5, 1, 5, 10,30, 60 minutes of agitation. Before each sampling, the mechanicalagitation was stopped for 2 minutes of sedimentation time.

A relevant amount of chunks were present at the bottom of the flask andthe slurry comprised of lignin appeared to be inhomogeneous.

The mechanical agitation was obtained by stirring the slurry comprisedof lignin at 250 rpm in both the experiments.

Concentration of dry matter of the lignin-rich composition wasdetermined by drying samples in an oven at 105° C. for 15 hours.

FIG. 5 reports the graph of percent complete dispersion of thelignin-rich composition in the slurry comprised of lignin. The percentcomplete dispersion is the concentration of dry matter of lignin-richcomposition in the slurry comprised of lignin normalized with respect tothe theoretical concentration.

The experiment demonstrates that by applying a vacuum the time needed toobtain a full dispersion of the lignin-rich composition in the slurrycomprised of lignin is strongly reduced, thereby enabling mixing energysavings, time savings and slurry tank volume reduction.

Slurry Pressurizing and Transport

After the slurry comprised of lignin is created it must be brought to apressure slightly greater than the lignin conversion reactor pressureplus the pressure from the slurry pump exit to the lignin conversionreactor (500), so that the slurry can be charged into the ligninconversion reactor (500).

The slurry comprised of lignin can be pressurized using a slurry pump(400). For the purposes of this specification the term slurry pump (400)is meant to refer to any pump which can reach the desired pressures,such as a piston pump and/or a syringe pump. A multi-stage centrifugalpump may also reach the required pressures. The slurry pump (400), whichis depicted as a piston pump used in the experiments will have an inletvalve (350). The inlet valve position can span the range from fully opento fully closed. Therefore, the inlet valve position can be selectedfrom the group consisting of open, closed and at least partially open,wherein open means fully open (the restrictions across the valve asmeasured by pressure drop are the minimum possible), closed means fullyclosed so that no liquid or gas can pass through the valve, and at leastpartially open means the valve is not fully closed and not fully open,but somewhere in between fully closed and fully open. The slurry pump(400) will have an outlet valve (450). The outlet valve can be presentin an outlet valve position selected from the group consisting of open,closed and at least partially open, with open, closed and at leastpartially open having the same meanings as for the inlet valve position.

The slurry pump (400) will further comprise a piston (420) and a pistonchamber (425). The piston (420) forms a seal inside and against thepiston chamber (425) to form a pump cavity. The size of the cavitydepends upon where the piston (420) is within the piston chamber (425).

The slurry comprised of lignin is passed through the inlet valve (350)which is in the inlet valve position of at least partially open or open(430A) into the pump cavity formed by withdrawing at least a portion ofthe piston (420) from the piston chamber (425). During this inlet step,the outlet valve (450) is in the closed outlet valve position (440B).The pump cavity will be at an inlet pump cavity pressure. After anamount of slurry comprised of lignin enters the pump cavity, the inletvalve position is changed to closed (430B), or in other words, the inletvalve is closed. A force is then placed on or applied to the piston(420) in the piston chamber (425) until the pressure of the slurrycomprised of lignin reaches the discharge pressure which is greater thanthe reactor operating pressure, also known as the lignin conversionreactor pressure or deoxygenation pressure. The reactor operates in theranges of 80 to 245 bar, 80 to 210 bar, 90 to 210 bar and 90 to 175 bar.Therefore the discharge pressure of the pump should also be in the aboveranges of 80 to 245 bar, 80 to 210 bar, 90 to 210 bar and 90 to 175 bar,but greater than the lignin conversion pressure. It should also be notedfor the purposes of this specification that the terms lignin conversionvessel and lignin conversion reactor are interchangeable.

At least a portion of the slurry comprised of lignin is discharged fromthe pump cavity by opening the outlet valve (450), also known aschanging the outlet valve position to a position selected from the groupconsisting of at least partially open and open. The piston (420) isfurther forced into the pump body to reduce the volume of the pumpcavity and push at least a portion of the slurry comprised of ligninthrough the outlet valve (450). The outlet valve (450) is connected tothe lignin conversion reactor (500) by tubing, piping or otherconnection. By connected to the lignin conversion reactor it is meantthat material from the pump cavity can flow through the outlet valve andinto the lignin conversion reactor (500) generally through a pipe, atube or through a series of connected pipes or tubes. In one embodimentthere may be a plurality of additional valves between the outlet valveand the lignin conversion reactor (500), such as a valve for isolatingthe lignin conversion reactor (500).

In order for the process to run in a continuous manner it is notnecessary that the slurry comprised of lignin is continuously introducedto the lignin conversion reactor (500). For example, when only onepiston pump is used, the slurry comprised of lignin is introduced intothe lignin conversion reactor (500) in steady aliquots or pulses. Thusthere are moments when there is no product entering the ligninconversion reactor. But, over time, the mass introduced into the ligninconversion reactor equals the mass removed from the lignin conversionreactor. One distinguishing feature between a continuous and a batchprocess is that, in a continuous process, the reaction is occurring orprogressing at the same time that either the slurry comprised of ligninis introduced into the lignin conversion reactor (500) and/or the ligninconversion products are removed from the lignin conversion reactor.Another way to state this is that the conversion (e.g. deoxygenating, orhydrogenating) in the lignin conversion reactor occurs whilesimultaneously, or at the same time, removing at least a portion of thelignin conversion reactor contents from the lignin conversion reactor(500). Such removal is done in a continuous manner which includes analiquot or pulse removal.

The previous art proposes the use of piston pumps or syringe pumps forhigh pressure reactor charging. However, the consensus of the art is touse check valves. This simple elegant approach has been used for years.However, as discovered by the inventors, check valves and other valveconfigurations will not work with a slurry comprised of lignin. Theinventors consulted multiple pump and valve experts and evaluated themyriad of solutions proposed by the experts, none of which allowed theslurry comprised of lignin to be continuously charged to the ligninconversion reactor. A pressure could not be maintained or could not bemaintained for long. The observations indicated that the tough, fibrousnature of lignin allows the lignin from the slurry comprised of ligninto get stuck in the valve seats and build up in areas of low flow orhigh impaction causing the valves to plug.

What was discovered is that a more complicated valving system worked. Itwas discovered that the industry standard and use of a simple checkvalve had to be replaced with a valve having a position that could becontrolled and that the valve should provide unrestricted andunobstructed flow of the slurry comprising lignin through the valve orits flow path. By unrestricted flow it is meant that the flow of theslurry comprising lignin through the valve (flow path) does not changedirections, such as in a bend, and does not increase in linear velocity,such as in a narrowing of the flow path. By unobstructed flow it ismeant that the flow path does not contain any additional elements, suchas the insert body of a butterfly valve, in the path of the slurry flowsuch that the slurry will have to flow around or strike the additionalelement when the valve is in the fully open position. Further, the flowpath does not contain additional dead zones, such as the seat groove ofa gate valve. Dead zones, such as the seat groove of a gate valve willfill with slurry when the valve is open and, when the valve is closed,the gate will compress the slurry into the groove which will allow foraccumulation and compression of the slurry comprised of lignin in thegroove. In this instance, over time the valve will not seat or seal, andwill fail to hold pressure.

By way of example, but not limitation, a valve that provides forunrestricted and unobstructed flow of the slurry comprising lignin mayinclude a ball valve, a full port ball valve or a full port fixed ballvalve. In contrast, traditional valves such as most globe valves, mostangle valves, most diaphragm valves, most butterfly valves and mostcheck valves restrict and/or obstruct the flow of the slurry comprisedof lignin and will cause the lignin from the slurry comprised of ligninto build up in areas of low flow or high impaction causing the valves toeventually plug or not seat or seal, and fail to hold pressure.(Examples of such valves are described in Chemical Engineers' Handbook,Fifth Edition, Perry & Chilton, p 6-54 through 6-57, 1973). In practice,this build up of lignin from the slurry comprised of lignin may occurquite rapidly, in some cases so rapidly that no amount of the slurrycomprised of lignin will be charged through the inlet valve and into thepump cavity. (See Slurry Pumping Experiment 1).

By removing the check valve, the system was no longer automatic withinthe valve but needed special additional controls to turn each valve onand off in a synchronized manner. Therefore, in direct opposite of theprior art, and what the pump and valve experts proposed to the inventorson many occasions, the process only functioned when the inlet valve(350) and the outlet valve (450) were not check valves, but valves thatprovide for unrestricted and unobstructed flow. (A check valve being avalve which prevents the reversal of flow). It is preferable that thepressurization process, discharge and ultimate charge into the reactorbe void of any check valves in the path of slurry flow. Alternatively,the slurry does not flow through a check valve into the slurry pump(400) to enter the reactor.

Different embodiments are available. For example there could be aplurality of slurry pumps comprising at least two piston pumps. Wherethere are two piston pumps each piston pump may have its own inlet valveand its own outlet valve (e.g. the first piston pump has a first inletvalve (350A) and a first outlet valve (450A) while the second pistonpump has a second inlet valve (350B) and a second outlet valve (450B)).The plurality of slurry pumps can be in a parallel configuration. It ispossible for two piston pumps in a parallel configuration to share thesame inlet valve (350) and/or outlet valve (450). Another configurationis where the inlet valve (350) and outlet valve (450) are the samevalve.

Eventually at least a portion of the slurry comprising lignin, a portionof which is in a solid form, is introduced into the lignin conversionreactor (500). The lignin conversion reactor will have a ligninconversion pressure and lignin conversion temperature. The ligninconversion pressure will be at least slightly less than the slurry pumpdischarge pressure which is at least the amount of pressure drop fromthe slurry pump (400) to the lignin conversion reactor inlet. Generally,the slurry pump discharge pressure will be greater than the ligninconversion pressure, with the slurry pump discharge pressure beinggreater than the lignin conversion reactor pressure plus the absoluteamount of pressure drop in the process from the slurry pump discharge tothe lignin conversion reactor (500).

Slurry Pumping Experiments

Experiments were conducted for charging a slurry comprised of lignin toa pressurized lignin conversion reactor. The following procedures wereapplied to all the experiments, unless differently specified.

De-ionized water was added to a lignin-rich composition obtained fromthe pretreatment of ligno-cellulosic biomass to obtain a slurrycomprised of lignin having a dry matter content of 20 weight percent ofthe mass of the slurry. The mixture was inserted into a blender (WaringBlender, model HGBSSSS6) and thoroughly mixed intermittently for one totwo minutes to reach a homogeneous slurry. The homogeneity of the slurrywas evaluated by eye. The slurry was inserted into a mix tank (340) withconstant agitation. The mix tank (340) was a stainless steel, dishbottom tank with a volume of approximately 1 L containing a standardlaboratory paddle mixer and a bottom discharge port connected to aChandler Quizix QX dual syringe pump having two pump cavities. Inletvalves (350) were inserted between the mix tank (340) and the two pumpcavities of the Chandler Quizix QX dual syringe pump. The ChandlerQuizix QX dual syringe pump was connected by tubing to a Parr 4575reactor equipped with a dual 45° pitched turbine blade, cooling coil,separate gas and slurry feed ports and a discharge dip tube (610).Outlet valves (450) were inserted between the two pump cavities of theChandler Quizix QX dual syringe pump and the Parr reactor. Between 200and 400 scfh of hydrogen at a temperature of 20° C. was inserted intothe Parr reactor to reach a pressure of 48.3 bar. The Parr reactor washeated to a temperature corresponding to 90% of the reaction temperatureand a continuous flow of Hydrogen was started into the Parr reactor.Final temperature and pressure in the Parr reactor varied between275-325° C. and 100 and 175 bar. The pressure was measured by means of apressure transducer (Ashcroft Type 62) connected to the Parr reactor.

The slurry comprised of lignin was passed from the mix tank (340) intothe first of the two pump cavities of the Chandler Quizix QX dualsyringe pump by changing the inlet valve position of the first inletvalve (350A) corresponding to the first pump cavity to the open position(430A) by means of an actuator. After the slurry comprised of ligninreached the first pump cavity, the first inlet valve (350A)corresponding to the first pump cavity was changed to the closed inletvalve position (430B) by means of an actuator. After the first inletvalve (350A) corresponding to the first pump cavity was closed, theslurry comprised of lignin was passed from the mix tank (340) into thesecond of the two pump cavities of the Chandler Quizix QX dual syringepump by changing the inlet valve position of the second inlet valve(350B) corresponding to the second pump cavity to the open position(430A) by means of an actuator.

After the first inlet valve (350A) corresponding to the first pumpcavity was closed (430B), the Chandler Quizix QX dual syringe pumppressurized the slurry comprised of lignin in the first pump cavity to apressure greater than that of the Parr reactor. While the slurrycomprised of lignin in the first pump cavity was being pressurized boththe first inlet valve (350A) and the first outlet valve (450A) wereclosed. After the slurry comprised of lignin in the first pump cavitywas pressurized to a pressure greater than that of the Parr reactor, thefirst outlet valve (450A) corresponding to the first pump cavity waschanged to the open position (440A) by means of an actuator, allowingthe pressurized slurry comprised of lignin in the first pump cavity tobe charged to the Parr reactor.

After the first outlet valve (450A) corresponding to the first pumpcavity was opened, the second inlet valve (350B) corresponding to thesecond pump cavity was changed to the closed position (430B) by means ofan actuator. After the second inlet valve (350B) corresponding to thesecond pump cavity was closed (430B), the Chandler Quizix QX dualsyringe pump pressurized the slurry comprised of lignin in the secondpump cavity to a pressure greater than that of the Parr reactor. Whilethe slurry comprised of lignin in the second pump cavity was beingpressurized both the second inlet valve (350B) and the second outletvalve (450B) were closed. The pressure of the Parr reactor is thedeoxygenation pressure and can range from 90 to 175 bar. After theslurry comprised of lignin in the second pump cavity was pressurized toa pressure greater than that of the Parr reactor, the first outlet valve(450A) corresponding to the first pump cavity was changed to the closedposition (440B) by means of an actuator. After the first outlet valve(450A) corresponding to the first pump cavity was closed, the secondoutlet valve (450B) corresponding to the second pump cavity was changedto the open (440A) position by means of an actuator, allowing thepressurized slurry comprised of lignin in the second pump cavity to becharged to the Parr reactor.

After the second outlet valve (450B) corresponding to the second pumpcavity was opened, the first inlet valve (350A) corresponding to thefirst pump cavity was changed to the open position (430A) by means of anactuator, allowing additional slurry comprised of lignin from the mixtank (340) into the first pump cavity to be pressurized and subsequentlycharged to the Parr reactor.

Slurry Pumping Experiments 1 and 2

For Slurry Pumping Experiments 1 and 2, the inlet valves and outletvalves were small orifice, rising stem valves from Vindum Engineering,Model No. CV-505-SS. These valves were recommended by an expert in thefield of slurry pumping, and were represented as sufficient for charginga slurry comprised of lignin to a pressurized reactor.

For Experiment 1, when the inlet valve corresponding to the first pumpcavity was changed to the open position, it immediately plugged withsolid lignin from the slurry comprised of lignin. No amount of theslurry comprised of lignin reached the first pump cavity, the outletvalve corresponding to the first pump cavity, or the Parr reactor.

For Experiment 2, an expert in the field of slurry pumping recommendedpressurizing the mix tank (340) to between 2.5 to 3 bar to assist withcharging the slurry comprised of lignin through the inlet valves intothe pump cavities. The expert represented that pressurizing the mix tank(340) would allow the slurry comprised of lignin to pass through theinlet valves into the pump cavities without plugging the inlet valves.When the inlet valve corresponding to the first pump cavity was changedto the open position, it immediately plugged with solid lignin from theslurry comprised of lignin without any amount of the slurry comprised oflignin reaching the first pump cavity, the outlet valves, or the Parrreactor.

Slurry Pumping Experiments 3 and 4

For Experiments 3 and 4, an expert in the field of slurry pumpingrecommended that the inlet valves and outlet valves be replaced withSwagelock Bellows Seal Valves, Model No. SS-HBS6-C. The inlet valves andoutlet valves of Experiments 3 and 4 had a larger orifice than those ofExperiments 1 and 2, and the expert represented that these largerorifices would allow the slurry comprised of lignin to pass through theinlet valves into the pump cavities without plugging the inlet valves.

For Experiment 3, when the inlet valve corresponding to the first pumpcavity was changed to the open position, it allowed a portion of theslurry comprised of lignin into the first pump cavity to be charged tothe Parr reactor. However, after a time of between 15 and 20 minutes theinlet valves again plugged with solid lignin from the slurry comprisedof lignin.

For Experiment 4, an expert in the field of slurry pumping recommendedpressurizing the mix tank (340) to between 2.5 and 3 bar to assist withcharging the slurry comprised of lignin through the inlet valves intothe pump cavities. The expert again represented that pressurizing themix tank (340) would allow the slurry comprised of lignin to passthrough the inlet valves into the pump cavities without plugging theinlet valves. When the inlet valve corresponding to the first pumpcavity was changed to the open position, it allowed a portion of theslurry comprised of lignin into the first pump cavity to be charged tothe Parr 4575 reactor. However, after a time of between 25 and 30minutes the inlet valves again plugged with solid lignin from the slurrycomprised of lignin.

Slurry Pumping Experiments 5 and 6

For Experiment 5, the inventors decided to replace the inlet valves withSwagelok 60 Series 3 piece Ball Valves, Model No. SS-62TS6. The outletvalves were the same Swagelock Bellows Seal Valves used in Experiments 3and 4. When the inlet valve corresponding to the first pump cavity waschanged to the open position, it allowed a portion of the slurrycomprised of lignin into the first pump cavity, which was subsequentlypassed through the outlet valve corresponding to the first pump cavityand charged to the Parr reactor. The process was run for a period ofapproximately two days, at which time the outlet valves became pluggedwith solid lignin from the slurry comprised of lignin.

For Experiment 6, the inlet valves were the same Swagelok 60 Series 3piece Ball Valves as those used in Experiment 5, however, the inventorsdecided to replace the outlet valves with Swagelok 60 Series 3 pieceBall Valves, Model No. SS-62TS6. When the inlet valve corresponding tothe first pump cavity was changed to the open position, it allowed aportion of the slurry comprised of lignin into the first pump cavity,which was subsequently passed through the outlet valve corresponding tothe first pump cavity and charged to the Parr reactor. The pump was thenable to continuously charge the slurry comprised of lignin into the Parrreactor without plugging the inlet valves or outlet valves. It was notnecessary to pressurize the mix tank (340) in order to charge thereactor.

Char Prevention

One of the difficulties in any continuous lignin conversion process isavoiding the formation of char. Char formation results in decreasedyields of lignin conversion products, and disrupts the continuous natureof the lignin conversion process, as the lignin conversion process mustbe shut down and the char removed from the lignin conversion reactorbefore continuing the process.

The Inventors discovered that, to avoid char, the deoxygenation, whichis the exposure of the lignin to hydrogen as either H₂ gas or via ahydrogen donor, occurs at a lignin conversion temperature and a ligninconversion pressure, wherein the lignin conversion temperature is in therange of greater than the boiling point of the liquid composition in thereactor at atmospheric pressure, and less than the critical temperatureof the liquid composition, with the lignin conversion pressure beinggreater than the bubble pressure of the liquid composition in thereactor at the lignin conversion temperature, subject to the conditionthat the lignin conversion pressure is selected so as to avoid theformation of char.

The liquid composition of the reactor is the composition of the liquidcomponents that are added to the vessel. For example, in one embodiment,the liquid composition is almost pure water with dissolved species. Inthe case of pure water the hydrogen would come from added hydrogen gas.In the case of pure water or substantially pure water, the bubblepressure is the vapor pressure of the water at the lignin conversiontemperature. In another embodiment, the liquid composition couldcomprise water and a hydrogen donor. This liquid composition has its ownbubble pressure and critical temperature forming the lower and upperboundary of the temperature range, subject to the additional conditionthat the lignin conversion pressure be selected so as to avoid charformation after two residence cycles, which can be visually verified byopening the reactor after two residence cycles and observing thepresence or absence of char—a dark residue coating the reactor. Thereactor will also be void of any liquid.

What has been discovered is that the lignin conversion pressure is alsoa function of the amount of gas exiting the reactor. The higher theamount of gas used, such as in hydrogen gas or nitrogen, the greater thepressure required. In the instance of a hydrogen donor, less gas is usedand thus a lower lignin conversion pressure is needed to prevent char.

The proper lower lignin conversion pressure can be easily empiricallyestablished as follows. One can determine the liquid composition chargedto the reactor. In most cases it will be water from the slurry andwhatever hydrogen donor compounds, if any, are used. The design willinclude a flow rate for the gas exiting the reactor. While thecalculations can be done manually, a commercial simulation package canbe used to determine the vapor liquid equilibrium conditions (bubblepressure) of the liquid mixture. This is demonstrated in Table 2 whichis the “calculated reactor pressure for liquid water” using water as theliquid. As can be seen by the table, the theoretical calculations are aclose approximation, but in the case of water, the actual pressure wasstill greater than the calculated amount based upon the pure components.Once the approximation is determined, the reaction can be conducted fortwo residence cycles, the vessel opened and examined for char. If thereis char, the reaction pressure is increased until there is no char andthus subject to the condition that no char is formed after two residencecycles.

A residence cycle is the amount of time to turn over the reactorcontents. If the residence volume is 4 L in the vessel and the vessel isbeing charged at a volumetric flow rate at operating conditions of 1L/hr, the residence cycle is 4 hours and 2 residence cycles is 8 hours.At 2 L/hr, the residence cycle is 2 hrs and 2 residence cycles is 4hours.

As demonstrated above the lignin conversion process should occur at alignin conversion temperature, where the lignin conversion temperatureis in the range of greater than the boiling point of the slurry liquidat atmospheric pressure, and less than the critical temperature of theslurry liquid, subject to the condition that the lignin conversionpressure is greater than the bubble pressure of the slurry liquid at thelignin conversion temperature and the lignin conversion pressure isselected so as to avoid the formation of char.

To avoid char formation, the lignin conversion pressure should beselected so that the lignin conversion pressure is greater than thebubble pressure of the slurry liquid at the lignin conversiontemperature. Bubble pressure is the sum of the partial vapor pressuresof all components in the lignin conversion reactor.

When the slurry liquid is comprised of water, the lignin conversionprocess should occur at a lignin conversion temperature below thecritical temperature of water.

Generally, the lignin conversion process will occur at a ligninconversion temperature in the range of 190° C. to 370° C. The ligninconversion temperature range is preferably selected from the groupconsisting of 190° C. to 370° C., 210° C. to 370° C., 220° C. to 360°C., 240° C. to 360° C., 250° C. to 360° C., 280° C. to 360° C., 290° C.to 350° C., and 300° C. to 330° C.

Where the slurry liquid is comprised of a hydrogen donor, the ligninconversion process may occur at a lignin conversion temperature in therange of 190° C. to 350° C. with 200° C. to 310° C. being morepreferred, 210° C. to 300° C. being even more preferred, and 210° C. to280° C. being most preferred.

The hydrogen donor may also be introduced into the lignin conversionreactor separately from the liquid slurry. The hydrogen donor may alsocome from the carbohydrate conversion step, thus the ligno-cellulosicbiomass is generating its own hydrogen for use in the process. In such aprocess, the hydrogen donor, such as ethylene glycol, could bemanufactured in the carbohydrate conversion step of FIG. 3 and passed tothe liquid slurry and introduced into the lignin conversion reactor viastream 325.

In order to avoid char it is also important to control the ligninconversion pressure as described above. The lignin conversion pressureis in a range preferably selected from the group consisting of 70 bar to300 bar, 80 bar to 245 bar, 82 bar to 242 bar, 82 bar to 210 bar, 90 barto 207 bar and 90 bar to 172 bar.

The continuous lignin conversion in the presence of carbohydrates shouldoccur at a lignin conversion pressure higher than the theoreticalequilibrium vapor pressure of water at the lignin conversiontemperature. It was directly observed that char was formed when thelignin conversion pressure was even greater than the calculated watervapor pressure at the lignin conversion temperature accounting for theexiting gas sweeping across the top of the liquid. No char was observedwhen the lignin conversion pressure was substantially higher than thecalculated water vapor pressure at the lignin conversion temperature.What was discovered is that to avoid char formation in a continuousprocess it was necessary to maintain at least a portion of the reactorcontents as a liquid, but to do so, required pressures much higher thanexpected or would have been predicted.

Char formation is not seen in batch reactor conditions because batchreactor conditions are always at theoretical equilibrium. When the exitsweeping gas is introduced in the continuous process, the equilibriumconditions no longer exist and the pressure required to keep at leastsome of the reactor contents as a liquid in the lignin conversionreactor is substantially higher than conventional wisdom or innovationwould teach. While process simulations can be made to initiallyapproximate the lignin conversion pressure at given conditions, theactual minimum lignin conversion pressure can be easily empiricallyestablished by increasing the pressure until no char is observed. Thosepracticing the invention are cautioned that the increase in pressure canbe large depending upon the flow rates from the reactor.

Char Prevention Experiments

The following procedures were applied to all the experiments, unlessdifferently specified.

De-ionized water was added to a lignin-rich composition obtained fromthe pretreatement of ligno-cellulosic biomass to obtain a slurrycomprised of lignin having a dry matter content of 20 weight percent ofthe mass of the slurry. The mixture was inserted into a blender (WaringBlender, model HGBSSSS6) and thoroughly mixed intermittently for 10 min.to reach a homogenous slurry. The homogeneity of the slurry wasevaluated by eye. The slurry was inserted into a mix tank with constantagitation. The mix tank was a stainless steel, dish bottom tank with abottom discharge port connected to a Chandler Quizix QX dual syringepump having two pump cavities. Inlet valves were inserted between themix tank and the two pump cavities of the Chandler Quizix QX dualsyringe pump. The Chandler Quizix QX dual syringe pump was connected bytubing to a Parr 4575 reactor equipped with a dual 45° pitched turbineblade, cooling coil, separate gas and slurry feed ports and a dischargedip tube. Outlet valves were inserted between the two pump cavities ofthe Chandler Quizix QX dual syringe pump and the Parr reactor.

Hydrogen at a temperature of 20° C. was inserted into the Parr reactorto reach a pressure of 48.3 bar. The Parr reactor was heated to atemperature corresponding to 90% of the reaction temperature andcontinuous flow of Hydrogen was started into the Parr reactor. Thepressure was measured by means of a pressure transducer (Ashcroft Type62) connected to the Parr reactor.

The slurry comprised of lignin was passed from the mix tank through theChandler Quizix QX dual syringe pump and into the Parr reactor byopening and closing the inlet and outlet valves in a manner that allowedthe slurry comprised of lignin to pass continuously into the Parrreactor.

Experiments were conducted according to the described procedure.Experimental parameters are reported in Table 1.

TABLE 1 EXPERIMENTAL PARAMETERS Lignin-rich Catalyst to Unreacted H2Flow Rate composition Residence Lignin-rich Lignin % Exp. Temp FlowPress. Slurry Solids Concentration time composition (% of Catalyst No.(° C.) (sccm) (bar) (mL/min) (g/min) (wt %) (min) ratio Theoretical)Loss 1 340 150 156.1 2.8 0.42 15 53 0.50 2 340 500 173.4 5.6 0.84 15 262.60 3 340 500 173.4 2.8 0.42 15 51 1.25 4 305 100 122.4 3.8 0.19 5 450.25 3.1 13.3 5 325 100 166.5 3.8 0.19 5 42 0.25 0.2 1.7 6 305 800 122.43.8 0.19 5 45 2.00 0.6 1.3 7 325 100 166.5 2.3 0.12 5 70 0.25 0.3 1.1 8305 100 122.4 3.8 0.57 15 45 2.00 20.8 18.4

Large amounts of char without liquid water was observed in the reactionproducts of experiments 1-3. No char and liquid water was observed inExperiments 4-8.

It is believed that it is necessary to have liquid present, such aswater in the liquid phase, for the reaction to progress as opposed todecomposition.

What was discovered was that even though the reactor was operated at atotal system (reactor) pressure well above the vapor pressure of waterat the 340° C. (146.1 bar) vs. the gas pressure, there was still nowater or solvent present.

TABLE 2 COMPARISON OF REACTOR CONDITIONS VS CHAR FORMATION Vapor Minimumcalculated Exp. pressure of Reactor pressure for Reactor No. Temp. purewater Liquid Water (bar) Pressure Char 1 340 146.1 165.3 156.1 Yes 2 340146.1 172.9 173.4 Yes 3 340 146.1 196.3 173.4 Yes 4 305 92.1 95.6 122.4No 5 325 120.7 125.8 166.5 No 6 305 92.1 116.3 122.4 No 7 325 120.7128.6 166.5 No 8 305 92.1 98.2 122.4 No

Catalyst Retention and Separation

Because the lignin conversion catalyst is present as free particles(625), and not a fixed bed, the lignin conversion catalyst needsseparated from the lignin conversion products. The catalyst particles(625) can be separated from the liquid lignin conversion products afterthe liquid lignin conversion products are removed from the ligninconversion reactor (500) by filtering, settling, centrifuging, solidbowl centrifuging, cycloning or other processes known in the art. Theseparated catalyst is then either re-introduced into the ligninconversion reactor for further reactions, treated for replenishment andthen reused, or discarded. These traditional methods are known.

It has been discovered that the free catalyst particles (625) can beseparated from the lignin conversion products in situ, that is withinthe lignin conversion reactor (500) while the continuous catalyticconversion of the lignin feedstock to lignin conversion products isoccurring. Thus, the lignin conversion products can be separated fromthe catalyst particles (625) during the continuous catalytic conversionof a lignin feedstock to lignin conversion products.

This separation is done by gravity settling, wherein the fluid linearvelocity (meters/min) of the lignin conversion products (liquid and gas)leaving the lignin conversion reactor is less than the gravitationallinear settling velocity of the catalyst particles (625) in theliquid/gas lignin conversion product stream exiting the reactor.Therefore, as long as the lignin conversion products being removed fromthe lignin conversion reactor are removed from the lignin conversionreactor at a linear velocity less than the settling velocity of thecatalyst particles (625) and from a point higher (relative to gravity)than the liquid level in the reactor, catalyst particles will stay inthe lignin conversion reactor.

The liquid level of the lignin conversion reactor is at the physicalinterface of the bulk liquid phase and bulk gas phase in the ligninconversion reactor (500). The bulk gas phase is a continuous gas phasewhich has a specific gravity which is less than the specific gravity ofthe bulk liquid phase. The bulk gas phase may have droplets of liquid inthe bulk gas phase. Likewise, the bulk liquid phase is a continuousliquid phase and will have dissolved gases and gas bubbles.

The height relative to the liquid level at which the lignin conversionproducts are removed from the lignin conversion reactor is called thedisengagement height. The disengagement height is greater than thecatalysts particles travel height which is the height the catalystparticles (625) will reach when carried along with the lignin conversionproducts. Because the settling velocity of the catalyst particles isgreater than the lignin conversion products removal velocity, thecatalyst particles (625) will eventually drop back into the ligninconversion reactor (500) so long as the disengagement height in thesettling zone as discussed below is large enough relative to the travelheight so that at least a majority of the catalyst particles (625) donot reach the point at which the lignin conversion products are removedfrom the lignin conversion reactor.

In practice, so long as the settling velocity of the catalyst particlesis substantially greater than the liquid lignin conversion productsremoval velocity, the disengagement height should be large enough sothat at least a majority of the catalyst particles (625) never reach thepoint at which the liquid lignin conversion products are removed fromthe lignin conversion reactor. For example, where the liquid ligninconversion products are removed through an “L” shaped dip tube having adip tube major length (612) and a dip tube minor length (614) as shownin FIG. 4, the disengagement point must be less than the dip tube minorlength (614). If the dip tube minor length (614) is one meter, thesettling velocity of the catalyst particles is 1.2 meters per second,and the liquid lignin conversion products removal velocity is 1 meterper second the liquid lignin conversion products will reach thedisengagement height (which is also the dip tube minor length (614)) inone second. Because the catalyst particles (625) have a settlingvelocity which is 0.2 meters per second greater than the liquid ligninconversion products velocity, the catalyst particles (625) will travelup the dip tube (610) at a velocity which is 0.2 meters per second less(0.8 meters per second in this example) than the liquid ligninconversion products travel up the dip tube. As a result, when the liquidlignin conversion products reach the disengagement height (which is alsothe dip tube minor length (614)) of one meter after one second, thecatalyst particles (625) will have only travelled 0.8 meters. In thismanner, the catalyst particles never reach the disengagement height andwill “settle” back into the lignin conversion reactor (500).

Conversely, if the settling velocity of the catalyst particles is lessthan the liquid lignin conversion products removal velocity, thecatalyst particles (625) will reach or exceed the disengagement heightand will be removed from the reactor. For instance, if the settlingvelocity of the catalyst particles is 0.8 meters per second and theliquid lignin conversion products removal velocity is 1 meter persecond, the catalyst particles (625) will be travelling at a velocity atleast equal to the liquid lignin conversion products. In this manner thecatalyst particles will reach the disengagement height at least at thesame time as the liquid lignin conversion products, and will thereby beremoved from the lignin conversion reactor (500) through the dip tube(610).

In a preferred embodiment, the lignin conversion reactor will have anagitation zone and a settling zone, also known as a decantation zone. Inthe settling zone, the liquid phase of the reactor is exposed to lessagitation than in the agitation zone. The settling zone can be createdby use of a dip tube as discussed below. The internal of the dip tubesees very little agitation and is thus the settling zone in thatembodiment. The settling zone can also be created by placing bafflesabove the agitator but below the liquid level to create a still spot.Another way is to have a separate reactor or vessel which does not haveagitation. This configuration is described in the bubble column section.The lignin conversion products are removed from the settling zone at alignin conversion products removal velocity. In order for more efficientremoval of the catalyst, the lignin conversion products removal issubject to the condition that to reach the point in the ligninconversion reactor which is higher relative to gravity than the liquidlevel of the lignin conversion reactor, the lignin conversion productsmust leave the agitation zone and pass through a portion of the settlingzone

FIG. 4 demonstrates an embodiment of the principles. In this embodiment,the product is removed via a dip tube (610), where the lignin conversionproducts must exit up and out the dip tube. As the lignin conversionproducts travel up the tube, the first catalyst particles (625) travelwith it. However, the first catalyst particle will have a terminal orsettling velocity—that is the speed at which the particle drops throughthe liquid lignin conversion products of the reactor. If one observescatalyst particles (625) coming out the dip tube (610), it is a simplematter to enlarge the diameter of the dip tube to reduce the ligninconversion products velocity relative to gravity (slow down the speed)so that the conversion products travel up the tube relative to gravityat a speed less than the speed at which the first catalyst particles aredropping down the tube, thus keeping the catalyst in the reactor. If onewished to purge the catalyst, or add new catalyst so that the oldcatalyst could be removed, one would reduce the diameter of the tube(increasing the flow rate) and have catalyst particles (625) flow out ofthe lignin conversion reactor (500). The catalyst removal andreplenishment can be done continuously so that a predeterminedpercentage of catalyst is removed and replenished on a continuous basis.

In practice, the catalyst particles (625) will vary in size and shape,each having a different settling velocity. Therefore, the preferredlignin conversion products removal velocity is less than the settlingvelocity of at least 75% by weight of the catalyst particles, with alignin conversion products removal velocity less than the settlingvelocity of at least 85% by weight of the catalyst particles being morepreferred, with a lignin conversion products removal velocity less thanthe settling velocity of at least 90% by weight of the catalystparticles being even more preferred, with a lignin conversion productsremoval velocity less than the settling velocity of at least 95% byweight of the catalyst particles being yet even more preferred, with alignin conversion products removal velocity less than the settlingvelocity of 100% by weight of the catalyst particles being mostpreferred.

The “75% by weight of the catalyst particles” means that 75% by weightof the total amount of catalyst in the reactor remains in the reactorand 25% by weight of the total amount of the catalyst in the reactor isremoved. Alternatively, the percent equals

100*R/[R+X]

Where R is the weight of the catalyst remaining, X is the weight of thecatalyst exited or removed from the reactor. The 100 is to make thenumber a percent.

One of ordinary skill can now easily see how a properly designed systemcould continually replenish catalyst—say add 5% by weight of newcatalyst while removing 5% by weight. Thus, the catalyst is constantlybeing turned over.

Catalyst Retention Experiments

Experiments were conducted for retaining catalyst in the reactor. Thefollowing procedures were applied to all the experiments, unlessdifferently specified.

De-ionized water was added to a lignin-rich composition obtained fromthe pretreatment of ligno-cellulosic biomass to obtain a slurrycomprised of lignin having a dry matter content of 20 weight percent ofthe mass of the slurry. The mixture was inserted into a blender (WaringBlender, model HGBSSSS6) and thoroughly mixed intermittently for 10 min.to reach a homogenous slurry. The homogeneity of the slurry wasevaluated by eye. The slurry was inserted into a mix tank (340) withconstant agitation. The mix tank (340) was a stainless steel, dishbottom tank with a bottom discharge port connected to a Chandler QuizixQX dual syringe pump having two pump cavities. Inlet valves (350) wereinserted between the mix tank (340) and the two pump cavities of theChandler Quizix QX dual syringe pump. The Chandler Quizix QX dualsyringe pump was connected by tubing to a Parr 4575 reactor equippedwith a dual 45° pitched turbine blade, cooling coil, separate gas andslurry feed ports and a stainless steel discharge dip tube (610) havingan outside diameter of 0.25 inches and an inside diameter of 0.152inches. Outlet valves were inserted between the two pump cavities of theChandler Quizix QX dual syringe pump and the Parr reactor.

The lignin conversion reactor pressure was controlled by a Mity MiteModel 91 Back Pressure Regulator (BPR) positioned in the ligninconversion reactor discharge line between the Parr reactor and theproducts receiver. The lignin conversion pressure was measured by meansof a pressure transducer (Ashcroft Type 62) connected to the Parrreactor.

The Parr reactor was charged with 150 mL of de-ionized water prior tobeginning the experiments. The lignin conversion reactor pressure wasincreased to 48.3 bar by way of 20° C. hydrogen. The lignin conversionreactor was heated to 90% of the lignin conversion temperature prior tocharging the slurry comprised of lignin to the lignin conversionreactor. After increasing the temperature to 90% of the ligninconversion temperature, additional de-ionized water was passed from themix tank (340) through the Chandler Quizix QX dual syringe pump into thelignin conversion reactor (500) at a rate of 2.8 mL/min. Hydrogen flowwas added to the lignin conversion reactor at a rate of 150 sccm. Atthis point, the temperature in the lignin conversion reactor wasincreased to 100% of the lignin conversion temperature, and the ligninconversion reactor pressure was adjusted via the BPR to the desiredoperating pressure as reflected in the experiments.

Slurry comprised of lignin was then charged to the reactor through theChandler Quizix QX dual syringe pump at a rate of 2.8 mL/min. The slurrycomprised of lignin was passed from the mix tank (340) through theChandler Quizix QX dual syringe pump and into the Parr reactor byopening and closing the inlet valves (350) and outlet valves (450) in amanner that allowed the lignin slurry to pass continuously into the Parrreactor. The lignin conversion products were continuously removed fromthe lignin conversion reactor (500) via the dip tube (610) and cooled toapproximately 35° C. before passing through the BPR. After passingthrough the BPR, the lignin conversion products were collected in astainless steel products receiver fitted with a vent line to allownon-condensable gases from the lignin conversion reactor to separatefrom the liquid lignin conversion products.

The lignin conversion reactor was allowed to reach steady stateconditions, and after four reactor residence cycles, the ligninconversion products were collected in the products receiver forapproximately one additional reactor residence cycle. At this time, allfeed streams to the lignin conversion reactor were stopped, and thelignin conversion reactor was isolated from the products receiver by wayof an isolation valve. The lignin conversion reactor was cooled toapproximately 30° C. and the pressure was reduced to atmosphericpressure by opening a vent valve.

The liquid lignin conversion products were mixed with an equal amount ofmethyl tertiary butyl ether (MTBE). This mixture was filtered through aBuchner funnel fitted with a Whatman #1 filter paper.

Catalyst Retention Experiment 1

For Experiment 1, sponge nickel catalyst was added directly to theslurry comprised of lignin resulting in a slurry comprised of 13.5weight percent lignin on a dry basis and 7.0 weight percent spongenickel catalyst on a dry basis. The sponge nickel catalyst had aparticle size range of between 10 and 40 μm. The lignin conversionreactor was operated at 340° C. and 156.4 bar, which is approximately 10bar above the vapor pressure of water at 340° C. At operatingconditions, the average residence time of the slurry comprised of ligninwas 53 minutes.

Surprisingly, after the experiment was stopped and the liquid ligninconversion products were filtered, very little catalyst was observed onthe filter paper, and in one instance, no catalyst was observed at all.Where catalyst was observed on the filter paper, it was observed as fineparticles of catalyst. When the Parr reactor was shut down and opened,it was surprisingly observed that nearly all of the catalyst remained inthe lignin conversion reactor.

Catalyst Retention Experiment 2

For Experiment 2, 28 g on a dry basis of the sponge nickel catalyst wascharged directly to the Parr reactor, along with the initial 150 mL ofde-ionized water, prior to beginning the experiment. No amount ofcatalyst was added to the slurry comprised of lignin prior to chargingthe slurry comprised of lignin to the lignin conversion reactor. As aresult, the slurry comprised of lignin contained 15 weight percentlignin on a dry basis. The lignin conversion reactor was operated at340° C. and 173.4 bar, which is approximately 17 bar above the vaporpressure of water at 340° C. Hydrogen flow rate was increased to 500sccm. Slurry feed rate and average residence time remained the same asin Experiment 1.

Surprisingly, after the experiment was stopped and the liquid ligninconversion products were filtered, it was observed that the majority ofthe catalyst remained in the lignin conversion reactor (500). Finerparticles of catalyst were observed on the filter paper. It was alsosurprisingly observed that, where higher rates of lignin conversion wereattained, less catalyst was removed from the lignin conversion reactoras evidenced by less catalyst present on the filter paper.

It is believed that the settling velocity of the catalyst particles isgreater than the velocity of the removal of lignin conversion productsfrom the lignin conversion reactor (500) through the dip tube (610).This results in the surprising and advantageous retention of catalyst inthe lignin conversion reactor. It is further believed that the fibrous,Velcro®-like nature of the lignin-rich composition in the slurrycomprised of lignin will attach itself to the catalyst particles (625)and remove them from the lignin conversion reactor where lower levels oflignin conversion are achieved. It is further believed that, whereremoval of all or a portion of the catalyst from the lignin conversionreactor is desired, all or a portion of the catalyst can be removed fromthe Parr reactor by decreasing the diameter and length of the dip tube,thereby increasing the velocity of the removal of lignin conversionproducts from the Parr reactor to a level greater than that of thesettling velocity of the catalyst.

Bubble Column Reactor

Although the process can be operated where the lignin conversion reactoris a continuous stir tank reactor (CSTR), the CSTR requires a highamount of energy input, and the high pressure required to convert ligninon a continuous basis results in an unreasonably large reactor whenutilizing a CSTR. It has been discovered that a bubble column reactorrequires less energy input and allows for a smaller reactor for acontinuous lignin conversion process.

One alternative to the CSTR is the ebullating bed reactor, as describedin U.S. Pat. No. 4,240,644. One version of ebullated bed is a bubblecolumn reactor. A bubble column reactor consists of at least onevertical cylinder at least partially filled with liquid. Gas is fed tothe bottom of the cylinder through a gas feed tube causing a turbulentupward stream of bubbles. In a preferred embodiment the gas may behydrogen or nitrogen. In a preferred embodiment the liquid may comprisewater. In a further embodiment the liquid may comprise a hydrogen donor.The gas flow could be nitrogen or hydrogen gas, at a sufficient rate tokeep the catalyst particles fluidized within the liquid components ofthe reactor.

In a preferred embodiment, the bubble column reactor will also comprisea gas distributor at the bottom of the vertical cylinder to allow foreven distribution of gas bubbles. A preferred gas distributor iscomprised of a material which is not corroded by the reactants, such asa stainless steel mesh.

A slurry comprised of lignin can be fed to the bottom of the verticalcylinder through a slurry feed tube. The amount of slurry comprised oflignin fed to the bubble column reactor can be varied to achieveincreased rates of lignin conversion as described in the experimentalsection below based on temperature, pressure, hydrogen flow, amount ofcatalyst and residence time.

In one embodiment a plurality of catalysts may be charged to the bubblecolumn reactor through the slurry feed tube. In another embodiment aplurality of catalysts may be charged directly to the bubble columnreactor prior to charging the hydrogen and/or slurry comprised of ligninto the bubble column reactor.

The reactor scheme for the bubble column may also include a secondcolumn for the disengagement of the solid unreacted lignin and catalystto flow by gravity into the bottom of the bubble column or ebullatingreactor and be recontacted with fresh gas.

The bubble column reactor may also comprise a heating element whichallows for regulation of the bubble column reactor temperature.Preferably this heating element comprises a plurality of heating coilswrapped around the vertical cylinder. In a preferred embodiment thebubble column reactor temperature is between 220° C. and 350° C. Thereactor conditions of pressure and temperature should be selected so asto prevent char formation as discussed earlier.

Bubble column reactor pressure may be varied based upon the bubblecolumn reactor temperature and gas flow rate as described in theexperimental section below. In a preferred embodiment the bubble columnreactor pressure is between 150 bar and 230 bar.

A dip tube may be inserted at the top of the vertical cylinder forremoving a plurality of the lignin conversion products to a productsreceiver.

In one embodiment the bubble column reactor may consist of a pluralityof vertical cylinders, each having a separate gas feed tube, a separateslurry feed tube and a separate dip tube.

What was found is that, by utilizing a bubble column reactor instead ofa CSTR, significant amounts of energy savings can be attained due to thelack of a separate stirring element. Additionally, the bubble columnresults in higher rates of conversion than a CSTR while converting theslurry comprised of lignin to similar products.

Bubble Column Reactor Experiments

The following procedures were applied to all the experiments, unlessdifferently specified. De-ionized water was added to a lignin-richcomposition obtained from the pretreatment of ligno-cellulosic biomassto obtain a slurry comprised of lignin having a dry matter solidscontent of 5 weight percent of the mass of the slurry comprised oflignin. The mixture was inserted into a blender (Waring Blender, modelHGBSS6) and thoroughly mixed intermittently at thirty second intervals(thirty seconds of mixing followed by thirty seconds without mixing) for10 min. to reach a visually homogenous slurry. (See Experimentalestablishing the ability of the Waring HGBSS6Blender to homogenouslydisperse on a quantitative basis). The homogeneity of the slurrycomprised of lignin was evaluated by eye.

The slurry comprised of lignin was inserted into a mix tank withconstant agitation. The mix tank was a stainless steel, dish bottom tankwith a bottom discharge port connected to a Chandler Quizix QX dualsyringe pump having two pump cavities. Inlet ball valves were insertedbetween the mix tank and the two pump cavities of the Chandler Quizix QXdual syringe pump. The Chandler Quizix QX dual syringe pump wasconnected by stream (1510) to a bubble column reactor having an insidediameter (1540) of one inch, a height (1545) of thirty inches, a heatingelement (1550), a gas distributor (1570) comprised of stainless steelmesh having a length of two inches, a slurry feed tube (1560) at thebottom of the column having a length of six inches for feeding thelignin slurry to the bubble column reactor, and a dip tube (1565) havinga length of eight inches connected to a transfer line (1580) at the topof the bubble column reactor for removal of reaction products to aproducts receiver. The products receiver was maintained at the samepressure as the bubble column reactor. The bubble column reactor furthercontained a vent (1520) connected to a rupture disk (1521) and apressure transducer (1522). The bubble column reactor further containeda thermal well (1590) for measuring temperature inside the bubble columnreactor during the experiment.

The slurry comprised of lignin was passed from the mix tank through theChandler Quizix QX dual syringe pump and into the bubble column reactorby opening and closing the inlet and outlet valves in a manner thatallowed the lignin slurry to pass continuously into the bubble columnreactor.

The inventors conducted a set of seven experiments. The results of theseexperiments are summarized below in Table 3 and Table 4.

Bubble Column Experiment 1

For Experiment 1, 43 g of Raney Nickel catalyst (1500) was chargeddirectly to the bubble column reactor, along with 150 g of liquid water,prior to beginning the experiment. Hydrogen was swept through the systemcontinuously at a gas flow rate of 300 scc/m through the gas feed tube(1530) and into the gas distributor (1570). The bubble column reactorwas heated to a bubble column reactor temperature of 310° C. to achievea target bubble column reactor pressure of 165.5 bar. Slurry comprisedof lignin was fed to the bubble column reactor at a rate of 3 mL/min.The slurry comprised of lignin was continuously fed to and removed fromthe bubble column reactor for a period of five hours or a total of 4.1residence cycles of slurry comprised of lignin through the reactor. Thetotal amount of slurry comprised of lignin passed through the system was45 g. When the inventors concluded the experiment, 11.1293 g ofun-reacted slurry comprised of lignin remained in the bubble columnreactor, however, in removing the un-reacted slurry comprised of ligninfrom the bubble column an unknown quantity was spilled.

What was observed was that the lignin conversion products were phenoloils that were nearly identical in composition as measured by G.C. MassSpectrometer to the phenol oils produced during a lignin conversionprocess in a continuous stir tank reactor (CSTR) (See FIG. 9).Conversion rate of the slurry comprised of lignin was 75.27%, not takinginto account the unknown quantity of un-reacted slurry comprised oflignin which was spilled.

Bubble Column Experiment 2

For Experiment 2, the inventors increased the bubble column reactortemperature from 310° C. to 318° C. The constant amount of slurrycomprised of lignin present in the bubble column reactor after reachingassumed steady state during the experiment was 15.2587 g. All otherconditions remained the same as in Experiment 1. When the inventorsconcluded the experiment, 15.2587 g of un-reacted slurry comprised oflignin remained in the bubble column reactor.

What was observed was that the increased bubble column reactortemperature resulted in a rate of conversion of the slurry comprised oflignin of 66.09%.

Bubble Column Experiment 3

For Experiment 3, the inventors reduced the amount of catalyst chargedto the bubble column reactor from 43 g to 21.5 g. The constant amount ofslurry comprised of lignin present in the bubble column reactor afterreaching assumed steady state during the experiment was 16.5924 g. Allother conditions remained the same as in Experiment 2. When theinventors concluded the experiment, 16.5924 g of un-reacted slurrycomprised of lignin remained in the bubble column reactor.

What was observed was that the reduced catalyst in the bubble columnreactor resulted in a reduced rate of conversion of the slurry comprisedof lignin of 63.13%.

Bubble Column Experiment 4

For Experiment 4, the inventors increased the bubble column reactorpressure from 166.49 bar to 172.4 bar and reduced the rate of slurryflow from 3 mL/min to 2 mL/min. Total run time was increased to sixhours and forty minutes, and total input of the slurry comprised oflignin was decreased to 40 g. The number of turns of slurry comprised oflignin through the bubble column reactor decreased to 3.62. The totalamount of slurry comprised of lignin present in the bubble columnreactor after reaching assumed steady state during the experiment was18.4116 g. All other conditions remained the same as in Experiment 2.When the inventors concluded the experiment, 18.4116 g of un-reactedslurry comprised of lignin remained in the bubble column reactor.

What was observed was that the reduced slurry flow resulted in a lowerrate of conversion of the slurry comprised of lignin of 53.97%.

Bubble Column Experiment 5

For Experiment 5, the inventors further reduced the rate of slurry flowfrom 2 mL/min to 1.2 mL/min. Total run time was increased to ten hours,and total input of the slurry comprised of lignin was decreased to 36 g.The number of residence cycles of slurry comprised of lignin through thereactor decreased to 3.26. The total amount of slurry comprised oflignin present in the bubble column reactor after reaching assumedsteady state during the experiment was 14.2125 g. All other conditionsremained the same as in Experiment 4. When the inventors concluded theexperiment, 14.2125 g of un-reacted slurry comprised of lignin remainedin the bubble column reactor.

At times of four hours, eight hours, and ten hours, the productsreceiver was de-pressurized and discharged. After four hours, theproducts receiver contained 0.89 g of phenol oils. After eight hours theproducts receiver contained 3.25 g of phenol oils. After ten hours theproducts receiver contained 0.97 g of phenol oils. Upon completion ofthe experiment, it was further observed that 2.4 g of phenol oilsremained present in the transfer line. When the residual solids weredrained from the bubble column reactor, filtered, washed with acetoneand Rotovapped, it was further observed that 1 g of phenol oils waspresent in the residual solids. Total, 8.51 g of phenol oils werecollected resulting in a phenol oils yield % based on the amount ofconverted slurry comprised of lignin of 39.06%. The phenol oils yield %based on the amount of slurry comprised of lignin charged to the bubblecolumn reactor was 23.64%.

What was observed was that, despite the reduced slurry flow, theincreased total run time resulted in a higher rate of conversion of theslurry comprised of lignin of 60.52%

Bubble Column Experiment 6

For Experiment 6, the inventors increased the gas flow through thereactor from 300 scc/m to 600 scc/m resulting in a bubble column reactorpressure increase from 172.4 bar to 187.2 bar. Total run time was alsoincreased to twelve hours. This resulted in an increased total input ofslurry comprised of lignin of 72 g. The number of residence cycles ofslurry comprised of lignin through the reactor increased to 7. The totalamount of slurry comprised of lignin present in the bubble columnreactor at any one time during the experiment was 23.5214 g. All otherconditions remained the same as in Experiment 4. When the inventorsconcluded the experiment, 23.5214 g of slurry comprised of ligninremained in the bubble column reactor.

At times of two hours forty minutes, five hours twenty minutes, eighthours, ten hours forty minutes and twelve hours the products receiverwas de-pressurized and discharged. After two hours forty minutes theproducts receiver contained 1.43 g of phenol oils. After five hourstwenty minutes the products receiver contained 3.27 g of phenol oils.After eight hours the products receiver contained 2.64 g of phenol oils.After ten hours forty minutes the products receiver contained 4.7 g ofphenol oils. After twelve hours the products receiver contained 3.57 gof phenol oils. Upon completion of the experiment, it was furtherobserved that 9.29 g of phenol oils remained present in the transferline. When the residual solids were drained from the bubble columnreactor, filtered, washed with acetone and Rotovapped, it was furtherobserved that 1.05 g of phenol oils was present in the residual solids.Total, 25.95 g of phenol oils were collected resulting in a phenol oilsyield percentage based on the amount of converted slurry comprised oflignin of 53.53%. The phenol oils yield % based on the amount of slurrycomprised of lignin charged to the bubble column reactor was 36.04%.

What was observed was that the increased gas flow rate resulted in ahigher rate of conversion of the slurry comprised of lignin of 67.33%.It was further observed that increasing the gas flow rate increased thephenol oils yield percentage both based upon the amount of convertedslurry comprised of lignin and on the amount of slurry comprised oflignin charged to the bubble column reactor.

Bubble Column Experiment 7

For Experiment 7, the inventors increased the bubble column reactortemperature to 335° C. resulting in an increased bubble column reactorpressure of 207.9 bar. The inventors also increased the amount ofcatalyst charged to the bubble column reactor to 85 g and the rate ofslurry flow from 2 mL/min to 3 mL/min. Total run time was decreased tofive hours. This resulted in a decreased total input of slurry comprisedof lignin of 45 g. The number of residence cycles of slurry comprised oflignin through the reactor decreased to 4.3. The total amount of slurrycomprised of lignin present in the bubble column reactor at any one timeduring the experiment was 12.082 g. All other conditions remained thesame as in Experiment 6. When the inventors concluded the experiment,12.082 g of slurry comprised of lignin remained in the bubble columnreactor.

At times of two hours, four hours, and five hours, the products receiverwas de-pressurized and discharged. After two hours the products receivercontained 2.69 g of phenol oils. After four hours the products receivercontained 1.34 g of phenol oils. After five hours the products receivercontained 0.36 g of phenol oils. Upon completion of the experiment, itwas further observed that 11.92 g of phenol oils remained present in thetransfer line. When the residual solids were drained from the bubblecolumn reactor, filtered, washed with acetone and Rotovapped, it wasfurther observed that 1.25 g of phenol oils was present in the residualsolids. Total, 17.56 g of phenol oils were collected resulting in aphenol oils yield % based on the amount of converted lignin of 53.34%.The phenol oils yield % based on the amount of slurry comprised oflignin charged to the bubble column reactor was 39.02%.

What was observed was that increasing the bubble column reactortemperature, amount of catalyst and gas flow resulted in a higher rateof conversion than any of the previous six experiments. Further, it wasobserved that the higher rate of conversion resulted in an increasedphenol oils yield % based on the amount of slurry comprised of lignincharged to the bubble column reactor, despite not resulting in anincreased phenol oils yield % based on the amount of converted lignin.

TABLE 3 Slurry H2 Total Exp. Temp. Pressure H2O Catalyst Flow SlurryFlow Lignin in Residence No. (° C.) (bar) (R) (g) (mL/min) (wt %)(scc/m) B.C. Cycles BC1 310 165.5 150 43 3 5 300 * 4.1 BC2 318 165.5 15043 3 5 300 15.2587 4.1 BC3 318 165.5 150 21.5 3 5 300 16.5924 4.1 BC4318 172.4 150 43 2 5 300 18.4116 3.62 BC5 318 172.4 150 43 1.2 5 30014.2125 3.26 BC6 318 187.2 150 43 2 5 600 23.5214 7 BC7 335 207.9 150 853 5 600 12.082 4.3 * Total slurry comprised of lignin in the bubblecolumn reactor is equivalent to the amount of unconverted lignin slurryremaining in the bubble column reactor upon shutdown. In BC1, 11.1293 gof unconverted lignin remained in the bubble column reactor, however anunknown quantity of un-reacted lignin was spilled upon removal from thebubble column reactor at the end of the Experiment resulting ininaccurate measurements.

TABLE 4 Rate of Total Phenol Oils Phenol Oils Catalyst LigninCatalyst/Ligni

Exp. Conversion Phenol Yield % Yield % Remaining in Remaining inRemaining in No. (%) Oils (g) (converted) (charged) Reactor (g) Reactor(g) Reactor (g) BC1 * N/A N/A N/A 24.03 * 2.16/1 BC2 66.09 N/A N/A N/A19.71 15.2587 1.29/1 BC3 63.13 N/A N/A N/A 15.83 16.5924 0.95/1 BC453.97 N/A N/A N/A 29.71 18.4116 2.16/1 BC5 60.52 8.51 39.06 23.64 27.6214.2125 1.94/1 BC6 67.33 25.95 53.53 36.04 30.81 23.5214 1.31/1 BC773.15 17.56 53.34 39.02 56.79 12.082  4.7/1 * 11.1293 g of unconvertedlignin remained in the reactor resulting in a rate of conversion inExperiment BC1 of 75.27%, however an unknown quantity of un-reactedlignin was spilled upon removal from the bubble column reactor at theend of the Experiment resulting in inaccurate measurements.

indicates data missing or illegible when filed

The lignin conversion process is considered a continuous process becausethe lignin conversion products are removed from the lignin conversionreactor (500) in a continuous manner. The reactants, such as thecomponent of the slurry comprised of lignin are generally introducedinto the lignin conversion reactor in a continuous manner as well. “Acontinuous manner” does not mean that that feedstock or products arecontinuously introduced or removed at the same rate. For example, whenonly one piston pump is used, the slurry comprised of lignin isintroduced into the lignin conversion reactor (500) in steady aliquotsor pulses. Thus there are moments, when there is no product entering thelignin conversion reactor. But over time, the mass introduced into thelignin conversion reactor equals the mass removed from the ligninconversion reactor. One distinguishing feature between a continuous anda batch process is that, in the continuous process, the reaction isoccurring or progressing at the same time that either the reactant feedsare introduced into the lignin conversion reactor and/or the ligninconversion products are removed from the lignin conversion reactor.Another way to state this that the conversion (e.g. deoxygenating, orhydrogenating) in the lignin conversion reactor occurs whilesimultaneously, or at the same time, removing at least a portion of thelignin conversion products from the lignin conversion reactor. Suchremoval is done in a continuous manner which includes a pulse removal.

The invented process converts the lignin in the feedstock to severaldifferent product types. As described later, the process conditions canbe set to produce one class of compounds at the expense of another classof compounds.

The lignin conversion can be considered as a deoxygenation of lignin.The lignin will not convert to a single product, but to a plurality oflignin conversion products. The feedstock comprising lignin is exposedto additional hydrogen (H₂) gas which can be added in the conventionalmanner according to the temperature and pressure of the ligninconversion reactor. The plurality of lignin conversion products may bevoid of ethylene glycol or propylene glycol.

There will also be a first catalyst present in the lignin conversionreactor (500). The reason it is called a first catalyst is that theremay be a second catalyst added to the lignin conversion reactor or asecond catalyst may be used to further react the lignin conversionproducts in a different step. While there may be a second catalyst, itis possible in one embodiment that there is only one catalyst, the firstcatalyst. The lignin conversion reactor may be void a second catalyst.

The lignin conversion products may comprise compounds which are found injet fuel, or the lignin conversion products may be further converted tocompounds comprising jet fuel.

The first catalyst can be any one of the catalysts known to catalyze thereaction of hydrogen with lignin. The first catalyst used in theconversion process is preferably a sponge elemental metal catalystcomprising at least one sponge elemental metal created by the Raneyprocess as described and claimed in U.S. Pat. No. 1,628,190, theteachings of which are incorporated in their entirety.

The process as claimed creates an alloy of at least a first metal and asecond metal dissolves the second metal out of the first metal, leavingbehind a finely divided elemental first metal with high surface area.This high surface area is often described as a sponge structure. Thepreferred first catalyst of the lignin conversion process is known asRaney Nickel, or where the finely divided elemental metal is nickel.Another preferred metal is a metal selected from the group consisting ofpalladium, platinum, nickel, ruthenium, rhodium, molybdenum, cobalt, andiron. Because water is a feature of the reaction, the catalyststructure, particularly its support must be hydrothermally stable. Dueto the heterogeneous nature, at least a portion of the first catalyst ispresent as a plurality of particles, or in particle form. At a least aportion of the first catalyst, if not all of the first catalyst, is notpresent as a fixed bed.

The first catalyst may or may not be supported or unsupported, but isgenerally not present as a fixed bed. If a fixed bed catalyst is used,the feedstock should be present as a liquid as opposed to a slurry sothat solids do not plug the pores of the fixed bed. The contemplation ofa fixed bed is part of the conception because it is believed that manyof the enabling principles of this process are applicable to both aslurry feedstock and a liquid feedstock without solids, or at least lessthan 1% solids by weight, of a slurry where the solids are present in asize less than the pores of the fixed bed.

The amount of the first catalyst can be expressed by the weight of theelemental nickel to the dry weight of the lignin feedstock, where theweight of the elemental nickel to the dry weight of the lignin in thefeedstock should be in the range of about 0.25 to about 2.0, with therange of about 0.3 to about 1.5 being more preferred with at least about0.5 to 1.0 being the most preferred. In one embodiment, the process isvoid of a catalytic amount of a second catalyst.

The second catalyst, if used, can be any of the standard hydrogenationcatalysts known, with the preferred second catalyst being the same asthe first catalyst. When the second catalyst is the same as the firstcatalyst, the amount of the second catalyst is the same as the amount ofthe first catalyst. When deoxygenation and dehydrogenation are conductedsimultaneously in the same vessel, there is no additional secondcatalyst added as the first catalyst and its amount becomes the secondcatalyst for the purposes of the dehydrogenation reaction.

There is also a preferred introduction of a third catalyst, which isdifferent from the first and second catalysts. The preferred thirdcatalyst is a Zeolite creating heterogeneous cites for the reactions toprogress in an acidic environment.

The plurality of conversion products preferably comprise at least oneproduct selected from the group consisting of carbon dioxide, methane,ethane, phenols, benzene, toluene, and xylenes.

It should be evident from FIG. 4 how the reaction process can beoperated as a CSTR—continuous stirred tank reactor.

The invention taught by the in situ separation using a dip tube isapplicable to almost any solid-liquid where the solids are present asfinely dispersed particles. This aspect of the invention is not limitedto a lignin conversion process.

Another embodiment of the process is that the plurality of ligninconversion products are cooled after leaving the reactor separating thevapor from the liquid and solids, with the back pressure regulator (700)located after the liquid solids separator (600), the pressure of thelignin conversion process can now be controlled.

The temperature of the lignin conversion products generated by thelignin conversion process are substantially greater than the temperatureof the steam, soaking and fermentation processes of the pre-treatmentand carbohydrate conversion processes that would precede the ligninconversion process. The inventors clearly contemplate that in theintegrated or co-sited operation that the heat from the ligninconversion products would be transferred to soaking, steam pretreatment,hydroylsis, and/or fermentation processes of the pre-treatment process.

Once these liquid lignin conversion products are obtained, they can thenbe subsequently converted to a number of different chemical feedstocksand intermediates. One preferred intermediate is at least one polyesterintermediate selected from the group consisting of ethylene glycol,terephthalic acid, and isophthalic acid. Once the intermediate is made,the conversion of the intermediate to polyester and subsequent articlessuch as soft drink bottles, beer bottles, and other packaging articlescan be accomplished using the conventional techniques known today andthose yet to be invented.

Since the lignin often comes with intractable carbohydrates, it may bepreferable to treat the feedstock first with a carbohydrate conversionstep to obtain carbohydrate conversion products. In a preferredembodiment, the carbohydrate conversion products are selected from thegroup consisting of alcohols, polyols, glucans, gluco-lignins andcellulose.

Fermentation is one such carbohydrate conversion step. Anothercarbohydrate conversion step and embodied in FIG. 1 is to create aslurry feedstock comprised of carbohydrates and lignin, feed it to acarbohydrate conversion reactor as described in US2011/312487 andUS2011/312488 and US2011/0313212 by pressuring the slurry feedstock asdescribed in this specification and feeding it into a first reactionzone and

a) contacting, the lignin slurry feedstock in a continuous manner, in afirst reaction zone, with hydrogen, water, and a catalyst to generate aneffluent stream comprising at least one polyol, hydrogen, water and atleast one co-product, wherein the hydrogen, water, and feedstockcomprising cellulose are flowing in a continuous manner, and wherein thecatalyst in the first reaction zone consists essentially of at least twoactive metal components selected from the group consisting of:

-   -   (i) Mo, W, V, Ni, Co, Fe, Ta, Nb, Ti, o, Zr and combinations        thereof wherein the metal is in the elemental state or the metal        is a carbide compound, a nitride compound, or a phosphide        compound;    -   (ii) Pt, Pd, Ru, and combinations thereof wherein the metal is        in the elemental state; and    -   (iii) any combination of (i) and (ii);        b) separating hydrogen from the effluent stream and recycling at        least a portion of the separated hydrogen to the reaction zone;        c) separating water from the effluent stream and recycling at        least a portion of the separated water to the reaction zone; and        d) recovering the polyols from the effluent stream.

After recovering the converted carbohydrates, such as the polyols fromthe effluent stream, to create a secondary feedstock stream comprisinglignin, the secondary feedstock stream comprising lignin can be againoptionally pressurized and fed into the lignin conversion reactor (500)to convert lignin into the phenols and other component in the pluralityof lignin conversion products.

In a preferred embodiment, the polyols, such as ethylene glycol andpropylene glycol may be used as a hydrogen donor to convert the ligninto lignin conversion products. In another embodiment, the hydrogen fromthe effluent stream may be used as a source of hydrogen to convert thelignin to lignin conversion products. Also, the water from the effluentstream may be recycled or reused as treatment water for pretreating theligno-cellulosic biomass feedstock.

Now that the fundamental operations have been explained, one can turn toFIG. 1 to describe one embodiment and its variations. As depicted inFIG. 1, the conversion of the ligno-cellulosic biomass can begin witheither pre-treated ligno-cellulosic biomass (20A or 20B) or untreatedligno-cellulosic biomass (10A or 10B). The A stream is fed into anoptional carbohydrate conversion process to convert the carbohydrates touseful products prior to converting the lignin. The chosen feedstockenters the carbohydrate conversion reactor (100) via stream (110).Additional reactants, such as hydrogen are added into (120). If theligno-cellulosic biomass is added as a slurry and a catalyst is used,the handling principles described creating the continuous process applyand reduce this process to practice as well. After conversion, thecarbohydrate conversion products are passed from the carbohydrateconversion reactor (100) to carbohydrate conversion product recovery(200) via stream (210). There can be two types of carbohydrateconversion products, one being gas exiting via (220). This gas could bemethane which can be converted to hydrogen by known technologies such assteam reforming. The hydrogen would be used either to convert morecarbohydrates or lignin by introducing the hydrogen into ligninconversion reactor (500) via stream (520). Should the embodiment produceethylene glycol, that ethylene glycol would be transferred via stream(230) to a polyester manufacturing facility which would convert theethylene glycol into polyester resin which is later converted tofinished polyester articles such as preforms and polyester bottles.

The lignin from the carbohydrate conversion process enters the ligninslurry creation step (300) via stream (310). The embodiment without thefirst carbohydrate conversion step is depicted by streams (20B) and(10B) respectively. As contemplated by the inventors, these coulddirectly feed, and have been proven to be continuously converted whenfed directly into the slurry creation step (300). Makeup water or othersolvent is added via stream (320) with the optional vacuum being appliedthrough stream (330).

If the ligno-cellulosic feedstocks of either (20B) or (10B) are alreadyin a slurry form, step (300) can be skipped and the streams (10B) or(20B) fed directly into the slurry pump or slurry pumps (400) via stream(410). The pumping system as described above increases the pressure ofthe slurry to greater than the reactor conversion pressure of the ligninconversion reactor (500). After pressurizing the slurry to greater thanthe reactor conversion pressure of the lignin conversion reactor, theslurry pump will discharge the slurry comprised of lignin through anoutlet valve (450) to the lignin conversion reactor (500) through stream(510). Lignin conversion reactor (500) will contain the lignin slurryand at least the first catalyst. Hydrogen will enter the ligninconversion reactor (500) at pressure through stream (520). As a CSTR,the lignin conversion products are passed up through dip tube (610),with the catalyst settling back down into the lignin conversion reactor(500). Vessel (600) is the liquid solids separator, with the gasby-products exiting the separation vessel (600) via stream (710) andpassing into the back pressure regulator (700) which controls thepressure of the whole system. After reducing the pressure, the gassesare passed through stream (720). If carbohydrates were introduced intothe lignin conversion reactor, then stream (720) will contain methane, aconversion product of the carbohydrates, thus the carbohydrateconversion process has been done in situ with the lignin conversion. Themethane can be further converted to hydrogen through steam reforming forexample and re-used in the process, thus making the process at leastpartially self-sufficient in hydrogen.

The solids from the lignin conversion process are separated from theliquids in step (600) with the solid passing in stream (620) and theliquids passing to the BTX conversion step (800) via stream (810).Stream (650) of FIG. 3 shows the separation of water from the ligninconversion process. While the water will be present in the liquid phase,there may be some water vapor present in (720) as well. As depicted inFIG. 1, in this embodiment, at least a portion of the water is re-usedto create or supplement the slurry comprised of lignin. As the ligninconversion process is a net water producer, some water will be purged instream (620).

The conversion of phenols to BTX is a well known chemistry with severalroutes being available. As the lignin conversion process producespredominantly phenols, the conversion of phenols by the known routes isconsidered well within the scope of one of ordinary skill. Once the BTX(benzene, toluene, xylenes) is formed it can be passed to a conversionstep to convert the BTX to terephthalic acid, react the terephthalicacid with ethylene glycol and make polyester resin and subsequentlyarticles from polyester resin (900) via stream (910). It is again wellwithin the scope of one of ordinary skill to convert these products toterephthalic acid, react the terephthalic acid with ethylene glycol tomake polyester resin and subsequently articles from the polyester resinsuch as films, trays, preforms, bottles and jars.

Integrated Process Experiments Material Preparation

The experiments used a composition obtained from wheat straw as astarting raw material.

The raw material was subjected to a soaking treatment in water at atemperature of 155° C. for 65 minutes then steam exploded at atemperature of 190° C. for 4 minutes.

The steam exploded material and the liquids from soaking material weremixed together and subjected to enzymatic hydrolysis, fermentation toethanol and distillation.

Detailed parameters used are considered not relevant for theexperiments, provided that the percentage content of the composition ispreserved.

The mixture of liquid and solids after distillation was pressed at 15bar and at a temperature of 80° C. to obtain a dense and compact solid,having a dry matter content of 55% and characterized by the followingcomposition on a dry matter basis.

TABLE 5 LIGNIN FEEDSTOCK ANALYSIS ELEMENT Percentage content Ash 13.04Lignin 49.71 Glucan 21.77 Xylan 6.81 Other compounds 8.67

The lignin-rich composition was subjected to a temperature lower than 0°C. and kept frozen until experiments execution.

Lignin Conversion Procedure

The following procedures were applied to all the experiments not usingthe bubble column, unless differently specified.

Frozen lignin-rich composition was naturally unfrozen until reaching atemperature of 20° C.

De-ionized water was added to the lignin-rich composition to reach thefinal lignin-rich composition concentration in the slurry planned ineach experiment. The mixture was inserted into a blender (WaringBlender, model HGBSS6) and thoroughly mixed intermittently (e.g. pulsedon for 30 sec, left off for 30 sec) for 10 min to reach a homogeneousslurry. The homogeneity of the slurry was evaluated by eye.

The slurry was inserted into a mix tank with constant agitation. The mixtank was a stainless steel, dish bottom tank with a bottom dischargeport connected to a Chandler Quizix QX dual syringe pump equipped withfull port ball valves, connected to the lignin conversion reactor. Thepump discharge was connected to the reactor with tubing.

The lignin conversion reactor was a Parr 4575 reactor equipped with adual 45° pitched turbine blade, cooling coil, separate gas and slurryfeed ports and a discharge dip tube. The reactor was charged with water(−220 mL) and catalyst (Johnson Matthey A-5000 sponge catalyst)according to the experimental conditions of each experiment and sealed.The weight of catalyst introduced is indicated as the ratio between theweight of the catalyst and the weight of dry matter of the lignin-richcomposition added to the lignin conversion reactor in one residencetime. Hydrogen at a temperature of 20° C. was inserted into the ligninconversion reactor to reach a pressure of 48.3 bar. The ligninconversion reactor was heated to a temperature corresponding to 90% ofthe reaction temperature and continuous flow of Hydrogen was startedinto the lignin conversion reactor. The lignin conversion reactor wasconnected to a products receiver, maintained at 25° C. The pressure wasmeasured by means of a pressure transducer (Ashcroft Type 62) connectedto the lignin conversion reactor and controlled by means of aback-pressure regulator (Dresser Mity Mite 5000, model 91) placeddownstream of the products receiver. Temperature was increased to thereaction temperature and the flow of slurry comprised of lignin wasintroduced into the lignin conversion reactor. The slurry flow rate wascalculated for obtaining the residence time of the lignin feed in thereactor in each experiment at the operating conditions. After a timecorresponding to 3 residence times steady conditions were considered tobe reached and solid and liquid reaction products were collected intothe receiver for a time corresponding to 1 residence time. The receiverwas depressurized to atmospheric pressure, the non-gaseous reactionproducts were extracted with methyl tert-butyl ether organic solvent,filtered, and the liquid phases were separated by a separatory funnel.

This system was continuously operated many times without shutting downfor up to 2 shifts (approximately 16 hours).

Experiments were conducted according to the described procedure.Experimental parameters are reported in Table 6.

TABLE 6 EXPERIMENTAL PARAMETERS Lignin-rich Catalyst to Unreacted H2Flow Rate composition Residence Lignin-rich Lignin % Exp. Temp FlowPress. Slurry Solids Concentration time composition (% of Catalyst No.(° C.) (sccm) (bar) (mL/min) (g/min) (wt %) (min) ratio Theoretical)Loss 1 340 150 156.1 2.8 0.42 15 53 0.50 2 340 500 173.4 5.6 0.84 15 262.60 3 340 500 173.4 2.8 0.42 15 51 1.25 4 305 100 122.4 3.8 0.19 5 450.25 3.1 13.3 5 325 100 166.5 3.8 0.19 5 42 0.25 0.2 1.7 6 305 800 122.43.8 0.19 5 45 2.00 0.6 1.3 7 325 100 166.5 2.3 0.12 5 70 0.25 0.3 1.1 8305 100 122.4 3.8 0.57 15 45 2.00 20.8 18.4

The experiments produced the following main products:

TABLE 7 Lignin Conversion Products for Table 6, Experiment 4 RelativeAmount (Area % of G.C.) Product ID Exp 4 Exp 5 Exp 6 Exp 7 Exp 82-Methoxyphenol 10.908 13.87 6.337 11.641 6.578 2,6 Dimethoxyphenol8.673 9.69 5.918 7.229 5.315 4-Ethyl-2-methoxy-phenol 8.139 9.728 8.7299.994 8.802 2,6-Dimethoxy-4-propylphenol 5.764 3.063 8.458 5.261 7.6372-Methoxy-4-propyl-phenol 5.118 2.322 5.417 4.042 5.798 4-Ethylphenol4.563 5.335 5.265 6.228 5.081/1.38 1-(4-Hydroxy-3,5-dimethoxyphenyl)-4.288 2.943 1.868 1.635 ethanone 2,6-Dimethoxy-4-ethylphenol 3.859 3.5296.363 2.634 3.02 Cyclopentanone 2.57 1.667 1.764 1.0872-Methyl-2-Cyclopenten-1-one 2.233 2.525 2.431 1.244 3 methyl?2-Methoxy-4-methylphenol 2.153 2.576 2.12 2.18 1.3772-methyl-Cyclopentanone 2.142 1.772 2.194 1.208 Phenol 1.932 2.8082.753/2.054 2,6-Dimethoxy-methylphenol 1.858 2.504 2.107 1.975 1.3652,6-Dimethoxy-4-(2-propenyl)-phenol 1.239 1.184 2.987 1.192 1.1792-Methyl-Cyclopentanone 1.324 1.208 >C20 Aliphatic 2.114 >C20 Aliphatic1.902 Formic Acid, 1,1, dimethlyehtyl ester 1.406 Cyclohexanol1.263 >C10 Aliphatic 1.146 >C20 Aliphatic 1.1312,3-Dimethyl-2-Cyclopenten-1-one 1.329 Eugenol 1.086 1.435Cyclohexanone, 3-ethenyl 1.074 1.559 Flopropione 1.471 >C20 Aliphatic1.228 ¹Those unidentified general compounds had a 20% match in thelibrary with the listed compound so they are noted only by the number ofcarbons.

Recycle of Waste Water Treatment

What has also been discovered is that the lignin conversion process ofcatalytic hydrogenation removes much of the contaminants from the waterof the stillage entering the process.

This was easily demonstrated by analyzing the chemical oxygen demand,also known as CODs of the stillage from the fermentation (carbohydrateconversion process) prior to the lignin conversion process and thenanalyzing the CODs from the water phase after the lignin conversionprocess.

Observationally, the untreated stillage in a glass sample containerappeared as a dark brown homogeneous solution. Prior to being processedin the lignin conversion process the liquid fraction was dark brown toblack, indicating a large amount of soluble contaminants. After passingthe water through the lignin conversion process (as part of theligno-cellulosic biomass feedstock) the water was separated from theorganic products. The water was no longer dark, but an amber straw gold.

When measured for CODs, the untreated stillage was 54,000 mg/L of COD.The CODs of the water after processing in the lignin conversion processwas 17,000 mg/L, a 69% reduction of CODs.

Thus, one embodiment of the process will produce an aqueous phase havinga COD concentration preferably less than 50% of the COD concentration ofthe aqueous phase of the lignin feedstock of the lignin conversionprocess. With less than 40% being more preferred and less than 32% beingmost preferred.

The aqueous phase can be recycled or reused, with or without further CODremoval or reduction of COD concentration, in the carbohydrateconversion step as the soaking water, the water of the steam explosionor other wash water or fermentation streams; or it can be re-used orrecycled in the lignin conversion step as part of the slurry creation ormake up water.

The re-use or recycle of just 10% of the aqueous phase has massiveimplications for the waste water treatment, which is a significant partof the expense of operating a carbohydrate conversion process, a ligninconversion process, or an integrated process.

The water from lignin-cellulosic feedstock was removed and visual andanalytically evaluated prior to being processed in the lignin conversionprocess.

This reuse of the water is depicted in FIG. 3, where at least a portionof the water from the reaction is separated from the lignin conversionproducts and re-used in the process. The water depicted as stream (650)could be used for the slurry at stream (320) or as part of thehydrolysis step at (120) of the carbohydrate conversion or used in thesoaking or steam explosion steps of the pre-treatment. If not reused,the water is generally sent to waste water treatment for furtherpurification and re-introduction into the environment.

Analytical Measurements 1. Composition of Lignin-Rich Composition

The composition of lignin-rich composition was determined according tothe following standard procedures:

Determination of Structural Carbohydrates and Lignin in BiomassLaboratory Analytical Procedure (LAP) Issue Date: Apr. 25, 2008Technical Report NREL/TP-510-42618 Revised April 2008 Determination ofExtractives in Biomass Laboratory Analytical Procedure (LAP) Issue Date:Jul. 17, 2005 Technical Report NREL/TP-510-42619 January 2008Preparation of Samples for Compositional Analysis Laboratory AnalyticalProcedure (LAP) Issue Date: Sep. 28, 2005 Technical ReportNREL/TP-510-42620 January 2008 Determination of Total Solids in Biomassand Total Dissolved Solids in Liquid Process Samples LaboratoryAnalytical Procedure (LAP) Issue Date: Mar. 31, 2008 Technical ReportNREL/TP-510-42621 Revised March 2008 Determination of Ash in BiomassLaboratory Analytical Procedure (LAP) Issue Date: Jul. 17, 2005Technical Report NREL/TP-510-42622 January 2008 Determination of Sugars,By Products, and Degradation Products in Liquid Fraction Process SamplesLaboratory Analytical Procedure (LAP) Issue Date: Dec. 8, 2006 TechnicalReport NREL/TP-510-42623 January 2008 Determination of Insoluble Solidsin Pretreated Biomass Material Laboratory Analytical Procedure (LAP)Issue Date: Mar. 21, 2008 NREL/TP-510-42627 March 2008 2. Composition ofLiquid Products

The composition of liquid products were determined by means of Agilent7890 Gas chromatogram and Agilent 5975C Mass Detector, according to thefollowing procedure and parameters.

Injector Parameters in the Gas Chromatogram:

Injection volume: 2 ulPulsed spilt injectionInjection pulsed pressure: 50 psi for 0.5 min

Temperature: 220° C. Pressure: 20.386 psi

Septum purge: 3 ml/minSplit ratio: 10:1Split flow 13 ml/min

Analytical Column:

Column: Restek RXI-5Sil MS, 30 meter, 0.25 mm ID, 0.5 um dfFlow (He): 1.3 ml/min

MSD Transfer Line: (Mass Detector)

Temperature profile: 280° C. for entire runColumn transfer line: HP-101 methyl siloxane-101 methyl siloxane:12m×200 um×0.25 um

Oven Parameters: (Connected to the Column) 40° C. for 1 min

12° C./min to 220° C. for 0 mins30° C./min to 300° C. for 17 mins

Detector Parameters: Temperature: 310° C.

H2 flow: 45 ml/minAir flow: 450 ml/minMakeup flow: 26.730 ml/min

MS Acquisition Parameters:

EM voltage: 1871Low mass: 10High mass: 350.00

Threshold: 25

# samples: 3MS source: 230° C.MS quad: 150° C.

Products and related percentage content relative to the weight of liquidproducts were identified by means of NIST 2008 peak identificationsoftware. Only products corresponding to an area greater than 1% of thewhole spectrum area are reported.

3. Composition of Solid Products

The filtered solids were dried and then ashed. The burnt portion wereconsidered unreacted lignin. The ash portion was considered nickelcatalyst.

4. Composition of Gas Products

The non-condensed gases were identified by gas chromatography.

We claim:
 1. A continuous process for the conversion of lignin feedstockcomprised of lignin and glucans, said process comprising: A. Slurrycreation of a slurry comprised of lignin from the lignin feedstock, B.Charging the slurry comprised of lignin into a lignin conversion reactorhaving a lignin conversion pressure, wherein the pressure of the slurrycomprised of lignin is higher than the lignin conversion pressure, C.Converting the lignin of the slurry comprised of lignin into ligninconversion products by contacting the lignin with hydrogen in thepresence of a first catalyst at a lignin conversion temperature, and D.Removing the lignin conversion products from the lignin conversionreactor.
 2. The process of claim 1, wherein the slurry creationcomprises the steps of: a. charging the lignin feedstock comprised oflignin and at least one slurry liquid at 25° C. to a vessel capable ofbeing subjected to vacuum, b. subjecting the vessel to vacuum for a timesufficient to disperse particles of the lignin to greater than 50% ofthe theoretical dispersion.
 3. The process of claim 1, wherein theslurry creation comprises the steps of: a. imparting high shear forcesto the lignin feedstock, b. adding a slurry liquid to the ligninfeedstock after application of the high shear forces.
 4. The process ofclaim 1, wherein the charging of the slurry comprised of lignin into thelignin conversion reactor involves pressurizing the slurry comprised oflignin using a piston pump having an inlet valve which can be present inan inlet valve position selected from the group consisting of open,closed and at least partially open, an outlet valve which can be presentin an outlet valve position selected from the group consisting of open,closed and at least partially open, a piston, a piston chamber, withsaid piston being sealed inside and against the piston chamber to form apump cavity, said pressurizing step comprising A. Passing the slurrycomprised of lignin through the inlet valve which is in the inlet valveposition selected from the group consisting of at least partially openand open into the pump cavity formed by withdrawing at least a portionof the piston from the piston chamber, with said outlet valve in theclosed outlet valve position and the pump cavity being at an inlet pumpcavity pressure, B. Changing the inlet valve position to closed, C.Increasing the pressure of the pump cavity to a discharge pressure byapplying a force on the piston in the piston chamber until the pressureof the slurry comprised of lignin reaches discharge pressure, E.Discharging at least a portion of the slurry comprised of lignin fromthe pump cavity into the lignin conversion reactor by changing theoutlet valve position to a position selected from the group consistingof at least partially open and open and forcing the piston further intothe pump body to reduce the volume of the pump cavity and push at leasta portion of the slurry comprised of lignin through the outlet valve;wherein the inlet valve and the outlet valve are both ball valves. 5.The process of claim 3, wherein the charging of the slurry comprised oflignin into the lignin conversion reactor involves pressurizing theslurry comprised of lignin using a piston pump having an inlet valvewhich can be present in an inlet valve position selected from the groupconsisting of open, closed and at least partially open, an outlet valvewhich can be present in an outlet valve position selected from the groupconsisting of open, closed and at least partially open, a piston, apiston chamber, with said piston being sealed inside and against thepiston chamber to form a pump cavity, said pressurizing step comprisingA. Passing the slurry comprised of lignin through the inlet valve whichis in the inlet valve position selected from the group consisting of atleast partially open and open into the pump cavity formed by withdrawingat least a portion of the piston from the piston chamber, with saidoutlet valve in the closed outlet valve position and the pump cavitybeing at an inlet pump cavity pressure, B. Changing the inlet valveposition to closed, C. Increasing the pressure of the pump cavity to adischarge pressure by applying a force on the piston in the pistonchamber until the pressure of the slurry comprised of lignin reachesdischarge pressure, E. Discharging at least a portion of the slurrycomprised of lignin from the pump cavity into the lignin conversionreactor by changing the outlet valve position to a position selectedfrom the group consisting of at least partially open and open andforcing the piston further into the pump body to reduce the volume ofthe pump cavity and push at least a portion of the slurry comprised oflignin through the outlet valve; wherein the inlet valve and the outletvalve are both ball valves.
 6. The process according to claim 1, whereinthe conversion of lignin of the lignin feedstock further comprises:deoxygenating the lignin to a plurality of lignin conversion products ina lignin conversion reactor containing reactor contents comprising aliquid composition which has at least one compound which is liquid at 1bar and 25° C.; while simultaneously removing at least some of thereactor contents from the reactor in a continuous manner; wherein thelignin conversion occurs at the lignin conversion temperature and thelignin conversion pressure, wherein the lignin conversion temperature isin the range of greater than the boiling point of the liquid compositionat atmospheric pressure, and less than the critical temperature of theliquid composition, and the lignin conversion pressure is greater thanthe bubble pressure of the liquid composition at the lignin conversiontemperature, subject to the condition that the lignin conversionpressure is selected so as to avoid the formation of char.
 7. Theprocess according to claim 5, wherein the conversion of lignin of thelignin feedstock further comprises: deoxygenating the lignin to aplurality of lignin conversion products in a lignin conversion reactorcontaining reactor contents comprising a liquid composition which has atleast one compound which is liquid at 1 bar and 25° C.; whilesimultaneously removing at least some of the reactor contents from thereactor in a continuous manner; wherein the lignin conversion occurs atthe lignin conversion temperature and the lignin conversion pressure,wherein the lignin conversion temperature is in the range of greaterthan the boiling point of the liquid composition at atmosphericpressure, and less than the critical temperature of the liquidcomposition, and the lignin conversion pressure is greater than thebubble pressure of the liquid composition at the lignin conversiontemperature, subject to the condition that the lignin conversionpressure is selected so as to avoid the formation of char.
 8. Theprocess according to claim 1, wherein the lignin conversion in thelignin conversion reactor is accomplished by: conducting the continuouscatalytic conversion of the lignin feedstock to the lignin conversionproducts in the presence of free catalyst particles in a ligninconversion reactor, with the lignin conversion reactor having a liquidphase and a gas phase with a liquid level at the interface between theliquid phase and the gas phase.
 9. The process according to claim 7,wherein the lignin conversion in the lignin conversion reactor isaccomplished by: conducting the continuous catalytic conversion of thelignin feedstock to the lignin conversion products in the presence offree catalyst particles in a lignin conversion reactor, with the ligninconversion reactor having a liquid phase and a gas phase with a liquidlevel at the interface between the liquid phase and the gas phase. 10.The process according to claim 8, wherein the removal of the ligninconversion products from the lignin conversion reactor is accomplishedby removing the lignin conversion products from the lignin conversionreactor at a lignin conversion products removal velocity at a point inthe lignin conversion reactor which is higher relative to gravity thanthe liquid level of the lignin conversion reactor wherein the ligninconversion products removal velocity is less than a settling velocity ofthe free catalyst particles.
 11. The process according to claim 9,wherein the removal of the lignin conversion products from the ligninconversion reactor is accomplished by removing the lignin conversionproducts from the lignin conversion reactor at a lignin conversionproducts removal velocity at a point in the lignin conversion reactorwhich is higher relative to gravity than the liquid level of the ligninconversion reactor wherein the lignin conversion products removalvelocity is less than a settling velocity of the free catalystparticles.
 12. The process according to claim 1, wherein the slurrycomprised of lignin further comprises water and at least a portion ofthe water is separated from the lignin conversion products and used in astep to process a ligno-cellulosic biomass material, said process stepselected from the group consisting of soaking, steam explosion,hydrolysis, fermentation or catalytic conversion of carbohydrates, orthe lignin feedstock slurry creation step (A).
 13. The process accordingto claim 11, wherein the slurry comprised of lignin further compriseswater and at least a portion of the water is separated from the ligninconversion products and used in a step to process a ligno-cellulosicbiomass material, said process step selected from the group consistingof soaking, steam explosion, hydrolysis, fermentation or catalyticconversion of carbohydrates, or the lignin feedstock slurry creationstep (A).